this video might be helpful
https://www.youtube.com/watch?v=xyOp2lyeAlY
The steel bolt had corroded onto the aluminium derailleur, thanks for your help, all fixed now!
@wjrh 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.
this video might be helpful
https://www.youtube.com/watch?v=xyOp2lyeAlY