Warmed it up again, left the throttle thermostat connected, and screwed in the black hex socket thing. Hunting has gone away, and idle speed down to sensible level. In fact, the black hex socket thing was well out, and I had to turn it several turns. It is now screwed up as far as it will go, but seems to run smoothly at a sensible rpm and no hunting. So thanks for your help! Distributor next. At least I'll end up with a good spare distributor, as there is apparently nothing wrong with the one I'm taking off. Cheers
