Being based in the Netherlands it's not as easy to point you in the right direction, but a bit of Googling should get you that far.
@Machine started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Being based in the Netherlands it's not as easy to point you in the right direction, but a bit of Googling should get you that far.