I'm with Dean on this one. I've seen his thoughts put into practice on other marques and, if done right, have produced excellent results.
There's no doubting your attachment to this car Paul, but if it was a 2.0 or a 2.1 it would have been scrapped by now. You seem to spend ever more time chasing metal and less time driving it. Time to make your mind up what you're going to do - strip it down completely to a rolling shell and weld everywhere that needs doing, or completely re-shell it.
Even if you were to drive over to France and bring the lhd shell back yourself it would take less time than welding everywhere - and a lot less hassle.
Write this year off, as no matter which you go you ain't gonna be driving that 24v, and do the job once . . . and do it right.
Personally I would re-shell it, make sure that the shell was sparkling before anything went into it, and not cut corners on anything. This doesn't have to cost a fortune to do as you already have the parts (and the knowledge) to do it.