So, thanks for all your replies on this matter.....................
Spent a day on this today. It may be fixed or it may not. To be fair I wouldn't offer any advice on this subject either!
So today took the clocks out, took out the low error gauge and cleaned it all up best I could. Put it back together and it worked.......for 5 mins......then literally died. So, I got the clocks back out and whipped out the spare binnacle, which happens to look in much better shape then the original one, and decided I would plug in this binnacle, as it was, and see how the temp gauge was (this had the high error gauge at this point). It seemed to work fine, so I took the decision it could be the pod or PCB and went about swapping everything over. This meant the rev counter, speedo and oil pressure/voltage gauges would need swapped over as they all have some sort of issue. The rev counter is bouncy and the needle slightly bent, the speedo obviously had the wrong mileage, and the voltage gauge was badly out of calibration.
First up, had to carefully swap over all the bulbs as I had been robbing this binnacle for years for spares. This is not easy in daylight going back and forward, in and out the car, to check all the bulbs are correctly located and working. Then crack open the binnacles and swap the oil pressure/voltage gauge, easy enough. Then the rev counter, a bit trickier but had done it before so not too bad, 3 screws and 5 nuts/washers and it comes out. Then the speedo, hadn't done this swap before, very fiddly, but got there in the end, unsure it would work though (see later on..). The speedo has 4 screws holding it, but when you start to remove it you see that it has a PCB underneath, that locates over pins (which doesn't move with the gauge, and is connected by wires, quite short, and routed round screw lugs for extra inconvenience!), that needs prized off with one hand as you hold the speedo with the other. A couple of rubber seating washers to deal with, and a black plunger thingy that sits on a slidey pole and locates into another device, no idea what it does. So, it's very tricky to remove and even trickier to refit. A three hand job if ever there was one! Thankfully, could play about with the other binnacle a bit to fumble my way through it. Of course, the removed incorrect speedo, reseated into the now reserve clock pod quite easily (luckily it turns out!) and of course the correct speedo, did not reseat very easily at all into the "live" binnacle. Anyway, much fiddling later it was in!
Bolted it all back together and re-assembled into car, all working including speedo, trip reset and odometer, result! Out for a test drive, 5 mins later we got the sky high temp again. FFS.
So it wasn't the binnacle itself. Clocks out again, split both pods and got back out the low error gauge, that had previously died earlier in the day. Swapped this back in and found the best rugby ball out my collection, back in the car and it worked fine surprisingly. Let it run up to temp, a few fan on and off cycles, and all was well. End of play after that so no test drive as had had quite enough of removing pods and swapping gauges back and forward by then! Was best to chuck it with it working and cling to the hope it would keep working I thought!
Remains to be seen if it will continue to work, fingers crossed. So I may well still have 2 x faulty gauges, or it could be rugby ball related (less likely I think) but I do have a much nicer binnacle than I did now installed! Will get another gauge if it plays up again.
Word of warning for any future clock pod dismantlers, the little orange needles on the gauges are so delicate and can be bent or twisted by breathing too hard! I don't know what they are made of but to the untrained eye it seems to be folded rice paper painted orange! Bare this in mind when you are trying to eradicate bits of dust on the gauge faces before you whack on the plastic cover and button it up! I tried using a hairdryer for this purpose and it looked like I had turned the ignition on!
Feel free to give me a shout on any binnacle related matters, apart from the f'kin temp gauge!
Cheers
Stuart