A follow-up from post #749 above.
This morning I started looking into the coolant warning issue. Having established that the level sensor is just a couple of prongs that angle downwards from the top/rear of the expansion tank, and are effectively shorted out by the coolant, I thought I would start there. Firstly, I removed the electrical connector and inspected the contacts both in the male and female parts - both were rather corroded or coated in dried up coolant. Using an electrical contact cleaner and a small detail file I cleaned them up and re-inserted the plug. Then I linked the two contacts in the plug with a piece of wire and turned on the ignition and was pleased that there were no faults showing.
Next I used the same file to clean the ends of the probes inside the tank. Once this was finished I turned on the ignition and still got no faults reported, ditto once the engine was running. I've used the car several times today and it remains fault free so I'm hoping to have solved that issue
