Well thanks to all the posts. I tried to fix it myself but I couldn't even get past the removing the screws for the plastic cover close to the dip stick.
Well I got quotes from Seat Windor and Seat Cambley and in the end the best was AVIT in Slough, not just for the work but the price and the service recived. I would recommend them now that I have used them, thanks Sunny!
I even got to speak to the engineer who did the work and they had to break the plastic cover to remove the screws. Looking at the themostat, it was stuck in the closed position. The Coolant temp sensor was the black one and AVIT just replaced it for the green seat item. AVIT even used OEM Seat parts and if you speak to Sunny the price is less than the Seat Dealer.