I just thought I'd give an update on this thread...
After two months of anguish and lots of late nights, home from work, babies bathed and in bed, started working on the bike about 10pm etc etc... I finally got my rebuilt engine fitted complete with its brand new four spring clutch, new con rods, reground crank, end feed conversion, Pazon surefire etc etc. I spent Saturday morning getting the timing spot on and doing the last few adjustments and yesterday I got out and rode just over 50 miles on it (albeit at never more than 10% throttle). The sun was shining and the engine purred along more beautifully than ever before, never once missing a beat.
And just once, for the most fleeting of moments, as I rode the last couple of miles home enjoying the warm breeze on my face and watching as the sun set over the Solway Firth and finally dipped behind the hills of southern Scotland in the distance, I nearly... very nearly... managed to forget how much it has all cost!
Cheers for all the help and support guys!