I had the head on my metro skimmed at an old school machine shop called Bannisters in Bamber Bridge, he's not VW specific but he did an excellent job. His address is:
3 Mounsey Rd,
Bamber Bridge,
Preston
PR5 6LS
01772 338970
I also know a guy in Bootle Liverpool who I actually work with and he has his own machine shop at home (although is a proper registered business), he's the best ive ever seen but does come at a cost. He's also an enthusiast and owns a beetle etc. I'll pass on his number if that works for you.
Harvey Engineering based in Manchester http://harveyengineering.co.uk/services/ , again ive used them through work and they've done bits and pieces for me in the past van related.