Hey Motorbill - didn't realise you were a Rover collector as well. The P6 is fondly remembered by lads of my age as the Motorway Patrol car. I'm pretty sure there was a Matchbox/Dinky model that nearly every kid had in their toy garage!
As for the original poster, I cant offer much except to comment on aluminium flywheels. One (the Moss supplied part) was fitted to my 67B on an otherwise stock engine by a garage too lazy to fit a new ring gear to the old wheel and machine it's clutch face I think. Anyhow, it hasn't affected drivability at all, as far as I can tell, but the engine is nice and perky for double declutching 
Ed
I want my MGB