Thanks guys, it says in the info on the instruction sheet that it was an actual VW based kit car of that time, like the Meyers Manx and the Empi Imp, but I've searched the internerd and found no leads.
No I'm not normally keen on the multi piece bodies Butz, but I've just opened up my next build, which is the Matchbox Porsche 356 Speedster Racer and the body is the same, with the side panels being fitted after the main body is fitted to the chassis!