Right, solved. I did find some M6 rivnuts and the Rivnut tool but what should have taken minutes took for ever because of the poor access under there. Later I discovered that YouTube has some film of home made tools which make inserting Rivnuts in out-of-the-way places much much easier. Next time I may make one of these as the proper Rivnut tools just over complicates things.
I had made up a simple rear fog light bracket from thin stainless steel to replace the original rotten effort so yesterday after adding a further two applications of Captain Tolley's stuff around the windscreen, I fitted the bracket and fog light. A bit of corrosion in the existing wiring and the live terminal in the lamp 0.5mm away from the end of the bulb, and it's now fully functioning.
I bought the car in the middle of the summer and have just used the heater for the first time. I takes a bit of time to actually chuck out some heat and the fan doesn't seem to make much difference, although it does eventually warm the car up. I do like the way the face level ventilators chuck out so much cool air.
With the evenings drawing in and it getting colder, the first frosts can't be far away so I am now thinking about emptying the engine/radiator coolant, flushing out the brown sludge with a hose, and re-filling with fresh water and antifreeze. I must dig out the Haynes to see how they recommend going about it. If I have to remove the top hose, I could take the opportunity to unbolt the rusty cross member and radiator stays and to give them a nice coat of black paint.
