Found the problem(s).
Part number 4 in the pic, like a little rod-operated bellows thingy, the rod's mounting clip on the rubber bellows has snapped. Any ideas where the hell I'll get one of these from?
Also pipes are crumbling in my fingers, so I'll have a bit of a replacing session with it all.
Going to look at a new motor tomorrow... more details soon - my S8 will be up for sale soon, once these last few niggles have been sorted.
