bigherb wrote:Don't worry too much it wouldn't be the first time it has happened, you can usually salvage it if the case is worn by fitting extra shims.
I found that a reassuring idea bigherb. As it turns out, thanks to the help I have had on here, I was able to check the distance from the top of the engine casing to the top of the dizzy drive

I know? Sophisticated or what? It's actually the muck on the straw that shows the 45.5 mm that I'm happy to live with - the pen mark was a bit clumsy.
I'd previously been able to check how the dizzy drive lined up - and I can't say perfect, but I'm going to say perfect.
Engine fired first time and needs a mixture adjustment and maybe idle speed increased a bit to make it driveable until it warms up. A tune is planned for the next week or so. I just want to get the old boy to Tatton and I'm very grateful for the help and encouragement I've had on this forum.
Cheers
Chris