• First delivered 26 March 1956 to German aristocrat Prince Franz-Ferdinand, Fürst zu Isenburg-Birstein
• With a fascinating back-story and in the ownership of the Scottish Tennent steel family from 1958 to 2006
• The subject of sympathetic work by marque and model experts HK-Engineering
• Presented in its striking original colours of DB 158 Weißgrau with original red-piped black leather interior and 58,700km believed recorded from new
• Matching numbers with luggage set, German registered

“On May 6, 1955, one side of a straight section of Autobahn between Munich and Ingolstadt was closed to allow journalists and Mercedes-Benz testers to try a 300 SL for top speed. Wind speeds were checked, and timing equipment was set up in a Volkswagen Microbus to measure speed in two directions over a flying kilometre.

“The fastest of the day was clocked by company tester Arthur Mischke with an average of 155.5mph” Karl Ludvigsen, model authority and former Gullwing owner, writing in his 2005 book Mercedes-Benz 300 SL, Gullwings and Roadsters, 1954-1964

After these exhaustive time trials, the 300 SL was borrowed by two British journalists who drove it from Munich to Frankfurt, averaging 78.6mph over 249 miles, an almost unbelievable pace to set on public roads in the mid-1950s, particularly given this car’s optional 3.09:1 ‘long’ axle.

The feat was all the more remarkable as the Gullwing employed in the test had, only days before, just completed 998 miles of the Mille Miglia in 11 hours, 29 minutes. Its engine was checked after the race and found to be in perfect order.

Instantly recognisable today, the immortal 300 SL Gullwing was the apogee of automotive technology of the time: the best of the best.

The Mercedes-Benz 300 SL ‘Gullwing’

When the Stuttgart Titan returned to motor racing in 1952 it did so with futuristic sports cars that looked as if they’d just landed from another galaxy. The Typ W194 300 SL was entered in five races that year and won four: victorious at Bern, the Nürburgring, Le Mans and the Mexican Carrera Panamericana, only just beaten on the Mille Miglia by an inspired Bracco at the wheel of a Ferrari.

Thanks to a spaceframe chassis that ran level with the driver’s waist, the 300 SL Coupé needed special doors, hinged at the roof and meeting the sills halfway up the side of the car. The ‘Gullwing’ was born.

Work was proceeding apace on the company’s challenger for 1953, a more svelte Gullwing racing car with a now fuel-injected motor, when Mercedes received an urgent request from its East Coast US agent, Max Hoffman. The factory saw the new car as a stop-gap before the straight-eight racers of 1954; Hoffman believed it could be marketed as an ultra-expensive roadgoing sports car.

Hoffman’s initial guarantee for 500 300 SLs clinched it. Rather than building the planned five specialised racing cars for the 1953 Mille Miglia, Mercedes productionised the prototype and the 300 SL was launched to the public at the February 1954 New York International Motor Sports Show.

Until final deliveries were made in early 1957, when the 300 SL roadster replaced it, 1,400 300 SL coupés found homes in the garages of the world’s wealthiest drivers. They were also raced and rallied hard by the most talented all-round professionals of the day. Stand-out Gullwing pilots included Olivier Gendebien (winner of the 1955 Alpine and Liège-Rome-Liège rallies), Wolfgang von Trips (who at one point led the 1956 Mille Miglia) and of course Stirling Moss, who finished second overall on the 1957 Tour de France.

Many sports cars, by virtue of their performance, are described as ‘racing cars for the road’. The meticulously built Mercedes-Benz 300 SL Gullwing, with searing acceleration and easy 130mph+ performance on everyday highways, really was one.

This Motor Car

According to a copy of the car’s original data sheet, 300 SL coupé (‘Gullwing’ was never used by the factory) chassis 6500040 was delivered in DB 158 Weißgrau (‘white-grey’) with 953 Schwarz (‘black’) leather piped in 641 Rot (‘red’) leather. Although the document is hard to read in places, it also mentions a black leather luggage (Koffer) set and a Becker-Mexico radio. The car was delivered in March 1956, though later Mercedes-Benz service records state January 1956.

Production of the 300 SL Gullwing finished later that year and the final cars are noted for a variety of improvements that resulted from the ongoing development of the model. As such, they are the ultimate Gullwings. Modifications for 1956 included: a new dashboard moulding; new distributor cap; exterior oil pressure pump; flexible oil pipes on engine to avoid vibration damage; and double-contact ignition.

This 300 SL was ordered new by German aristocrat Prince Franz-Ferdinand of Isenburg-Birstein, a typical first owner of one of the world’s most expensive cars. His title, Fürst, is from Old High German. The family were Prussian landowners and headed the House of Isenburg-Büdingen, with relations in the House of Prussia that ruled Germany until 1918, and the Kingdom of the Two Sicilies.

Franz Ferdinand was born on 17 July 1901 and married Countess Irina Tolstoy on 27 July 1939. Their grandson, Alexander, lives in the family seat of Schloss Birstein today. The prince died on 9 December 1956, only a few months after taking delivery of his exciting new Mercedes and the car was sold. A short time later, the fortunes of ‘6500040’ took an extraordinary turn via German industrialist Oscar Waldrich, who might well have bought the 300 SL on Franz Ferdinand’s death.

Waldrich took over his father’s machine tool concern HA Waldrich in Siegen, Westphalia, after WW1. The company greatly expanded during this time, becoming a world-leader in roll-grinders and roll-lathes, the very heavy and expensive precision machinery used to make the massive rollers found in steel mills. One customer was the well-established Scottish firm RB Tennent & Sons Ltd, who supplied rolling machinery to the steel mills of Lanarkshire. It already had close links to the German iron and steel industry after mid-19th century founder Robert B Tennent established his company around German-patented machinery.

Although the Waldrich factory had been bombed to destruction in 1944, later, in the 1950s, thanks to West German Chancellor Konrad Adenauer’s Wirtschaftswunder (‘economic miracle’) business was booming. RB Tennent’s then managing director James Tennent was on excellent terms with Oscar Waldrich and the two companies enjoyed such a good business relationship that James’s two sons, John Howard and James Norman, were offered extensive periods at the Siegen factory in the mid-1950s in which to complete their studies before taking over the family firm.

By this time Oscar Waldrich was in his mid-70s and was clearly a highly individual company boss: he was always chauffeur-driven by a German former racing driver in his Mercedes-Benz 300 SL Gullwing, this car, chassis 6500040.

When it was time for Howard to return to Scotland, Oscar Waldrich asked if he would like something by which to remember his time in Germany. “I would really like your Mercedes 300 SL sports car!” Howard replied, somewhat in jest. “Well,” said Waldrich, “I won’t give it to you, but I will sell it to you. For one Pfennig.” A handwritten note in the car’s history file states 300 SL XGD 4 was “presented to J Howard Tennent on the completion of his engineering apprenticeship by Dr Ing Oscar Waldrich (owner) HA Waldrich Maschinenfabrik”. In truth, the gift was also likely a way of cementing the business relationship between the two companies for generations to come.

The nearly new Mercedes sports car was sent to the UK where it was registered in Lanarkshire XGD 4 on 17 February 1958, though speaking to Kidston SA in 2020, the final Tennent family owner, Robin, remembers the car took many months to arrive in the UK. Although it was Howard that mainly used it, the asset was shared equally with his brother.

Robin Tennent remembers summers in the 1960s in the car, when his father used it on high days and holidays, the excitement, the “precision click of the doors closing”. They were happy times. By 1970, though, the car was used less and less, Norman Tennent had relinquished his share in it and Howard stored it at his company address. In 1976, following the buy-out of RB Tennent, it was not advisable to keep the car in a factory that was no longer owned by the family. Howard eventually retired and Norman had been running another plant in Crewe, Cheshire.

Perhaps it was time to sell. A letter dated 13 February1979 from Mercedes-Benz in Stuttgart thanks Howard Tennent for his offer of the car and requests the asking price and chassis number. Tennent replied a week later but had no idea of value. He does confirm it is chassis 6500040. Two months later, a handwritten letter dated 22 April 1979 to son Robin Tennent from a Mr C Berg of Sunbury-on-Thames offers the family £16,500, on the basis that Berg would spend a further £3,000 preparing the 300 SL for rallies and exhibition but entries would be made in the Tennent name. The approach was not taken up.

With little space to store the car at home, an offer of display at the Doune Motor Museum in 1989 was the perfect answer and the car would stay there until its closure in 1998. Sadly, a burglary at Howard Tennent’s home in 1989 resulted in the theft of the original black luggage set including some tools.

Howard Tennent died in 1991, so the Gullwing passed to his two sons Robin and John. Robin bought out John in 1995 and from then onwards was the sole guardian of the family’s treasured car. Throughout this time, it was looked after by main agent Mercedes-Benz Western Automobile Company in Edinburgh. Copies of invoices on file from 1999 to 2005 are generally billed to Mrs Tennant of 12 Lady Jane Gate, Bothwell, Glasgow. Invoice 357129, dated 20 May 2000, records an odometer reading of 46,053 – in kilometres as the instruments had never been changed.

A letter from Werner Kühn of Siegen D-57080, Germany, dated 29 November 1999 addresses Robin Tennent and referencing his father Howard, Herr Kühn asks after the white-grey 300 SL. He remembers its days in Siegen where his own father worked, and mentions were it ever to be for sale he would be interested – or at least could the family bring the car back to visit its spiritual home. The offer was declined: Robin Tennent had promised his two daughters and son they would all use the family Gullwing when they were married, and only then would it be sold.

He was true to his word. After three weddings, in 2002, 2004 and 2006, and some 48 years in the Tennent family, ownership of the highly original 300 SL was transferred on 1 May 2006 to veteran British specialist in classic Mercedes, Ivan Page-Ratcliff. The mileage stated on the V5 was 47,521 and Robert Brown Tennent the owner, Robin’s full name.

Page-Ratcliff, for so many years the doyen of the Gullwing market in the UK, sourced cars for German specialist HK-Engineering GmbH, one of the world’s foremost experts in the marque and model. Speaking to Kidston SA in 2020, the man who has sold at least 100 300 SL Gullwings in a career that started at main agent Brooklands Motor Cars in the early 1950s, remembers it as “the best Gullwing I have ever driven apart from the new cars in 1954.” He found confetti from the last wedding in the interior.

The car was sold to HK-Engineering shortly afterwards and some time later the desirable Gullwing, which had spent almost half a century with one family, was sent to the famous Kirchplatz 1, 82398 Polling, address for sympathetic work aimed at maintaining its originality while overhauling many mechanical components. The experts were presented with a 300 SL with its original interior, a largely undamaged body in very good condition and an original engine. After a lengthy period in the workshop, all the time taking great care to preserve the car’s originality, ‘6500040’ emerged from recommissioning and was acquired by one of HK’s clients.

Six years later it returned. A report conducted by Alexander Monn-Weiss of the German appraisal company Classic Data dated 6 June 2012 concluded: “Overall very nice original condition with fantastic patina. Except from the front part, all body panels are untouched. The original interior is hard to find in another car and distinguishes this car. The engine has been improved for better reliability.” The report notes an odometer reading of 57,792km. The “front part” to which he refers must be the bonnet, as Robin Tennent in 2020 recalls a visit to a small service station where an unskilled mechanic tried to open it the wrong way using two screwdrivers… Robin also confirmed that the car was never fully painted in all its years with the Tennents and the odometer reading was correct.

Our client bought the car from HK-Engineering in 2012 and has carefully looked after it since. It now shows 58,700km and given the car’s extensive history file we believe this is the distance covered from new. Gullwing owner Simon Kidston tried the car in November 2020 and agrees with Page-Ratcliff: this one drives exactly as a Gullwing should: inviting, exciting and rewarding.

The market for good 300 SL Gullwings – instantly recognisable as classics from Detroit to Dubai – has weathered the recent slowdown in demand for collectable cars. An interesting colour and original body, engine and interior are pluses. A history file that includes work by one of the best, HK-Engineering, is another. Add to this a fascinating and romantic back-story, and ownership in one British family for 48 years and you have a stand-out car.