Looks like a good base.....I find the whole cleaning process quite relaxing and gives a massive sense of achievement when you can stand back and admire your handywork, The front grills on mine had a similar greyness to them as yours, I managed to save the lower middle one, but have now fitted some aftermarket ones for the rest, fit is virtually perfect and really makes the front end look newer.
I enjoy a good before and after cleaning gallery, please make sure you give us some photos of those inner arches when done!How are you finding the Ramair??
Nice work cleaning out the grot inside the arches - any particular product used in there?
The peeling lacquer is likely the original paint. It's very thin on the roof. A respray generally uses a more generous layer than the factory. Mine is the same colour and also peeling in places. MK5s weren't the best made of Golfs unfortunately.