many thanks Doug, I have managed to obtain a pair of tappet block retainers from a member, so all is well!!, re the breathing, yes, mine is exactly as you describe, and is per as your picture, I attach two pics of the crankcase, front half through via these two small holes the engine breaths into the tappet area is this sufficient?, also I show the area around the main bearing, a breather slot??but to where?.
has anyone installed a reed valve breather or, is it necessary?
best regards david