The guys at St Mary's NHS Trust wanted me to give them a plug. They run two projects for those working in the sex industry.
Praed Street Project is for women associated with the sex industry. The clinic offers:
Free confidential testing and check ups for STI's. Free certificates issued after results (normally one week).
Vaccinations against Hep B
HIV testing
Cervical smears
Free condoms and emergency contraception
http://www.praedstreetproject.org.uk/
Guys also have their clinic called The Working Men Project
http://www.wmplondon.org.uk/
Both projects are based at St Mary's Paddington London. Great people there who are always helpfull.