My Blackbird was fitted with standard caterham brakes - Ford M16 calipers. James Whiting did not build any Blackbirds just the Fireblades.
I fitted a HiSpec Ultralite 4 Caterham kit that bolts straight onto the standard 232mm disc set up, no mods required. Weight per caliper 0.9KG. Price £250.00 + VAT including new discs, pads, hoses and 5.1 fluid. They work fine.
Nick