thanks for reply mate, the bore is fine, i just fubard the bottom of the conrod as when i came to undo the rod bolts one was seized and i mean REALLY seized. So after i had broken a few tools on it and completely chewed up the head of the bolt, i took an angle grinder to it. A move i now regret as i managed to take a mm or two of mating surface off the conrod. bugger. Never mind, thats what u get for employing cowboy tactics.
Should be able to source a new set of pistons and rods for cheap enough anyway, will be easier than getting 1 balanced etc.

Aid