Spoke to a VW specialist who also owns a GTI and he said the radiators are quite common when there's slow leaks occurring so going to get the car pressure tested tomorrow morning i think and will see what happens from there.
Also if the radiator would need replacing. would it be the type of thing i could have done through my warranty? I have had the car two to three weeks and i was given a three month warranty as part of the deal which i was told would cover the engine and gearbox. I don't have the warranty booklet with me as i left it at home up north but just wondered in the worst case scenario would it be covered?
Thanks,
Carl.