right, did a search this morning online and the results so far are:-
fault with the break light switch on the pedal??? why??? it’s the glow plug light!!
fault with the relay for the glow plugs. this sounds more likely
I’ve found a couple of people who have had this problem and VW just replaced those 2 parts. (then charged a fortune I guess)
So I’m going to order them and fit them first I think before I consider a garage.