Thanks for the replys guys, It looks to be a bit of a dead end as I won't even be able to get the car cert'ed with a centre lock wheel. The car is half circuit, half street car so it would still have to be legal for the road.
Just as a matter of interest Risking, What would the uprights etc go for? There is a race GTR over here that wants to run ex-V8 super car wheels, The uprights might be right up his alley.