Last two mornings (freezing) when I have turned my car over the light has come on but I turn the car off and back on again and it goes. Level is spot on anyone know what could cause this?

Coolant level sensor in expansion tank. Single skin tanks, the contacts can be scraped clean, or new tank and cap (£14)

Got a part number for the tank? I've only just replaced the cap with one from Awesome (black)

On the fabia the contacts can't be cleaned so it's a new tank. Just phone up your local dealer and ask for a tank, no need for part nos. £15 or so if I remember correctly.

I found this guide extremely helpful when I changed mine last year.