In reply to Dave the Rave:
I got the zip on a nice PHD minimus down jacket a professionally repaired a while ago and in that case it was fairly marginal whether it was worth it or not.
I certainly wouldn't be doing the same with my 7 or 8 year old RAB Generator Alpine synthetic jacket. It's nowhere near as warm now as it was when new and has been relagated from serious Winter use.
Ignore those who don't seem to know what things actually cost in the real world. Even my local alterations place which is crazy cheap for most stuff charged me well over £30 for a proper full replacement (as opposed to the cop out of sewing the new zip onto the fabric of the old one) and that was about 5 years ago. That's not counting the fact that for previous repairs before I found this place, I had ludicrous quotes or no interest in the job from multiple places locally or online.
People don't really want awkward jobs like that, so it's not something that you're likely to ever get a cheap quote for and any tailor or seamstress who's already busy is (at least from my experience) fairly likely just to fob you off.
Loads of repairs are worthwhile if you're stuck at home over lockdown with the equipment and lots of free time, however as soon as something requires two lots of postage it rapidly becomes less viable.
As a fall back, always worth considering selling it cheaply online as it is. Someone with a sewing machine might want a bargain and you can put a few quid towards a new one.
Post edited at 00:37