Apologies for the late reply. I thought everyone had stopped discussions but there is half a dozen new ones since I last read.
Re the Hasselblad prices - in fairness, they said to send it for an £80 service, where they spend an hour servicing it, re-aligning screws etc and checking it over. Only if a confirmed fault was found would it be the £250.
But that doesn't matter because a few days after my last post, odly enough, I was just holding my Blad and admiring it generally, and I tipped it upsdie down, at which point I heard a little click. Surprise surprise, the lens then came off. My friend RJ rekons the lens to body screw might just be slightly out of line. I have shot a roll wit it since but not had it developed so can't confirm all is well, but the camera now seems to be OK, having sat in a warm and dry house for a few months. I suspect the damp bag that I left it in was the cause of all this.