Gordor, if the coolant level is fine, chances are it's a faulty level sensor on the coolant cap. On my MK5 I had 4 of them replaced under warranty and once on the Scirocco. Exactly the same symptoms you describe - coolant warning light on, but with mine, normally taking the cap off, putting it back on and re-starting, cured it for that cycle until I had it replaced.
Thank you
that's comforting. The warning light didn't come on this morning and both temperatures have been fine, so this sounds like the issue. She's due an oil change shortly so I'll keep an eye on it until then and get this, the keys without the silver bits and the speaker system sorted.
