OK, so I've been to my garage, stripped the single piston, BMW's excuse for a calliper
of my CSL and tried the Porsche BREMBO 4 pots, for size. Looks like the calliper covers about 80 % of the 345 mm disc (pix below) but I'm not sure this will work
. It seems I'll be needing bigger callipers
... something like the BIG REDS off the 928 GTS or 993 TURBO