LATEST REPORT : "SO FAR SO GOOD"
It's been pretty cold here in the Charente these last few days (a few degrees colder than in England for once) so I've been working in short bursts. My coolant cicuit held pressure even after several days, so that was good. I then used the pressure from my pressure pump to purge the circuit from the two purge bolts. Before going further I got on with adjusting the headlights. I'll post my findings once I've finished this - see
https://www.sportsmaserati.com/inde...-xenons-adjusting-headlamps-headlights.34855/
I then put the RH wheel back on and refitted the protection under the engine to make the car was drivable again. With the new thermostat the car settles at about 85°C when on the move, (5°C outside), climbs beyond 90°C when stationary, the fans turning on at around 93°C, and off again at about 90°C, all of which sounds pretty good to me. The 85°C on the move is definitely a few degrees hotter than it used to be. All very encouraging. I've been trying to replicate the fail-to-start-from hot, so far thankfully without success. I've also not yet had another P0128 code. All looking good, but it's early days yet.
Not sure I'm ready to avoid petrol forecourts quite yet, Ian, but it's definitely "so far so good" - thanks again for your encouragement!
I'll report back after a few more outings.