Cheers for your help guys, we have actually made one up out of an old Tripod head bolted into a metal plate. means it is really easy to move around when needed. Actually looks like a bigger version of the ones in the links above. Managed to get it all done for about $40 and took about 35 mins.
Christopher: you wanted to know what sort of car I'm racing? it's a 1975 BMW 2002.
Racing at Pukekohe on Sat & Sunday in the Leisuretime series.