TecMoto do excellent repairs - they fixed a fist-sized hole in my seat unit when I came off. They do proper plastic welding repairs rather than just filling holes full of filler and fibreglass.
They're near Romford off J28 of the M25, so dunno how easy that is for you?
http://www.tecmoto.co.uk/ or 01708 343 916 - they also do DSC discount if you are a member.