Yes was turning okay.

No low coolant alarm fitted, I checked the cam belt this morning and seems to be intact. The AA man just listened to the engine as I turned it over and said head gasket has gone. It didn't lose all of its coolant and the temperature gauge was at just above 3/4.

It lost power on the M5 on a very hot day, did have the air conditioning on at the time, it did lose some of its coolant. It is are daily runner so doesn't stand for long periods of time.

Battery is still as power but when turning the key its just the engine is turning over but not firing up, AA man said sounds like there is no compression and didn.t go any further than that and just loaded it up. I fear its not going to be a good out come. So i have posted in the Techie section. But ...