Thanks again today for the help chaps.
I really appreciate the amount of time all of you have generously given up from your weekends to help me out.
SHE'S ALIVE!
After a horrifying spectre of having to remove the engine again after seeing it in, finished, & running (noisily!) because of an inexplicable clutch problem, my brother has saved the day and saved us from removing the engine unnecessarily again tomorrow.
All that remains really now is to get the exhaust on it, clean it, and drive it around hoping the check engine light will go away!
You're a bunch of diamond geezers - cheers chaps.