What is it ?

I found this photographic print in amongst hundreds of other prints last weekend.I have no idea what it is or where it was taken or why I have the print.The scene looks English and I guess it is the 1960's and the "car" has what may be a registration disc on the windscreen and a number plate so it must have been road registered.It seems to be three wheeler -or perhaps there are twin rear wheels very close together so that it does not need a differential.It is obviously rear engined and aircooled as there is no front radiator.Surely it is a home built special or was this a prototype for an economy vehicle and was someone hoping to manufacture and sell it ?