Thanks for all the comments lads,
I have to say.... Apart from the power (obviously) the drivability is the best thing about this engine. If (for any reason) I want to pootle along it will drive at 2,000 rpm in 5th perfectly fine, it will also start up with just a turn of the key and idles like a normal engine - let alone the excellent fuel economy.
I really am chuffed to bits with Sandys engine, can't fault it one bit!