This years entry form states:
The permitted rear tyres at all venues in the 2012 BRCA Off-Road National Championship are :- Schumacher Mini-Spike (Original & Mk.2) and Ballistic Buggy Mini-Spike.
This to me means that you could run front Schumacher / Ballistic mini spikes on the rear axle, as no part number is specified, only a type.
