Re-Painting the underside

Our antifouling is in need of scraping off as it is now very thick, the primer has started to flake of the aluminium in some spots. I have been touching it up for a couple of years but it is probably time to strip it back and re-paint the underside. Does anyone have any experience of having this work done or could recommend a company (south coast of England as we will need to sail the boat over and have just about run out of holidays!)