Last Castle Combe Action Day the Reyland cars were lapping at 1:18 - 1:19 with a clear(ish) track.

For reference, Cossie's with a road set up suspension and 330 - 350 BHP will usually manage 1:24 - 1:26 on a tidy lap.......Anything under 1:24 in a road car is a VERY good time.