Thanks for the advice Fullrace,
i have ordered the 'Karl' engine. Hopefully i can take some pictures along the way as a build thread, broken taps and all :-)
I spent ages making a stainless cam follower for the M90 engine only to break a 3mm tap in the hole i was making for the pushrod, so this topic is at the front of my mind at the moment.
Kind regards
Ade