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Captain Donald Marcus Kelway Marendaz was born in Glamorgan in 1897 to a Swiss family
He left to join the Royal Flying Corps No 35 Squadron in 1916 training as a pilot and serving in France until invalided out in 1918 with the rank of lieutenant.
Shortly afterwards started Marseel with Charles A. Seelhoff, a company making gearboxes for the Emscote car. Emscote didn't take all the gearboxes they made so the surplus were used with Coventry-Simplex engines to make complete cars.
The company changed its name to Marseal Motors in 1923 when Seelhoff retired.
1926 After a brief period in the City of London he sets up D. M. K. Marendaz in Camberwell building cars that looked like Bentleys but no action taken against him by Bentley as he posed no threat and had little money
He raced cars at Brooklands built by Graham-Paige
1928 New 24 hour record at Brooklands in the 1.5 litre class of 1,425 miles at an average of 73 mph in a Marendaz Special. Drivers were M. K. Marendez, K. N. Forest and L. L. Hanks the owner of the car. 
1930 Damages awarded against him of £1,850 to Yvonne Harvey Brown over the death of her husband in a motor accident on the Kingston Bypass on 29th November 1929 caused by the negligent driving of Marendaz 
1932 He starts Marendaz Special Cars in Maidenhead but this fails in 1936
He moves to Bedford and starts a flying school
1936 Appeals against conviction for speeding at Whyteleafe but loses. 
1936 He establishes Marendaz Aircraft to build biplanes but these never reached production.
He was also a supporter of Oswald Moseley leader Of the British Union of Fascists and this led in 1940 to him being jailed on security charges but he was released after a few days.
After the war he emigrated to South Africa where he built small diesel engines and formed Marendaz Diesel Tractors.
1958 Sale of Nantgawr and Swansea porcelain, the property of DMK Marendaz announced and total reached is £5,050. 
1965 On trial in South Africa accused of fraud 
1972 He returned to England
1988 Died at the age of 91.