Dropped the car off at my mechanics today, got my new air condition condensor fitted, he checked the system and gassed it with dye and told me keep an eye on it.
I washed the car a found a trace yellow dye on a pipe, took a picture and my mechanic could not apologise enough, said it must be a weak seal / rubber and he would have a look at it as soon as I could get back.
He also quickly banged on my GSi steering wheel, which I need to get used too, and some new boot struts.