I was once depping for a band on an outdoor gig.
Outdoor, so nowhere to put cases, nowhere to warm up and nowhere to go to the loo.
Was told off for warming up because it was "Unprofessional" to play on stage.
Where the hell else was I meant to go?!
I will second Dave's suggestion of Mick Rath. The man is a genius with all things trombone.
If you can't get up to Huddersfield though, Dennis Wedgwood in Cardiff is a good repairer.
If you go to Wedgie though DO NOT TAKE A GIG BAG!!! Hard cases only (Unless you want to incur his wrath)