To update you all on this it turned out to be the fan switch that was leaking (quite badly). I hadn't noticed as I'd been parking on lawn due to some work on the house so hadn't noticed any puddles! Took it to my local garage and they said the fan won't come on if the coolant drops too low hence why it overheated. It must have been leaking for a while. Anyway, £20 switch and an hours labour to fit and flush and replace coolant and all sorted now! I had another episode the other day where it wouldn't start and called the AA out. He immediately thought fuel pump so went about removing all the back seats to get to it only to realise it was just the relay that was at fault by the windscreen and I had a spare so that's sorted too now. Funnily enough the AA guy worked for Mangoletsi in the mid 90s and didn't think much of the GTV saying "it was junk even when it was new" and "you must like driving...and spending money". I just told him it's still better and cheaper than a new Vauxhall or something equally dull on finance that will lose half it's value in a year.