Well, dropped in to the local clutch/brake place and had a chat. I described the problem to them, and they reckoned the thrust bearing too. I also tried putting my foot behind the clutch pedal and lifting it slightly, and that too seemed to stop the squealing. Strange.
The bad news is that even for a minor look at things, it's going to be a couple of hundred bucks just for the time involved So I'm inclined to leave it as is until the clutch lunches itself fully, and then replace it all.
Anyone had experience with RPM1195 or 1195 Heavy Duty clutches? Or Centerforce? I'm thinking the 1195 Heavy Duty might be the go eventually...