For most repairs we'd recommend sending your kit to Lancashire Sports Repairs. They've been servicing the outdoor world forever and do an amazing job. If you want to change a broken zip, re-stuff down jackets, resole boots or whatever, they are fantastic!
Gearshack have
no commercial connection with LSR; we've just been using them for a long time and they are truly great. They are a tradition of the outdoor world in the UK.
Their website is at:
www.lancashiresportsrepairs.co.uk