The grill looked familiar, that gave it away in the end, it's a Mini MG I found attached picture first.
So I's called de MG Gnat. It's a Cooper 'S' shell with a grille of an MG 1100 and remodeled it to the width of a Riley 'Elf'.It was made in the MG factory in Abingdon with bought or cadged parts from them and the BMC Competitions Department. The historical cars of MG, were saloons called 'Magna' and 'Magnette'. Both were combined to make 'Gnat'.