Thank you very much. I used some time for better research than before. Here my result:This car was registered ADM 691 in Mold, Flintshire, in 1937. Who built this 'Special' remains a mystery. In the 60's -vaguely- this 'Special' found its way to the USA, was auctioned 2017 by Bonhams, and is now owned by Chris Baltazar, Mass., USA.
This 'Special' has been built on a '36 Triumph Gloria chassis. The builder installed a Coventry-Climax-engine, which had been replaced by an 1.5-litre-4-cyl. from a later Dolomite (still in the car). The bodywork originated from an pre-war Aston-Martin-Ulster. Before Baltazar bought this car, this body -still visible on the puzzle-picture- was auctioned separately. Baltazar is on the way to recreate this coachwork.
Attached picture of the 50's