Good repair people are getting hard to find, not just for cameras but as mentioned for watches, fountain pens, and any matter of old gadget. That being said there are still people out there, I dont know any Nikon people in the UK but a drop into your local camera shop may help. I have had a variety of the older Nikon F era stuff come across my bench (FE, EM, FT, F3). With the low prices of bodies these days I don't mind working on them my self as I can generally just chuck it (into my parts pile) if I really really mess something up.
If you elaborate a bit more on what is wrong we may be able to point you to some DIY or home fix soltuions. If its just the light seals you can do that at home pretty easily and you can get the seals on
Ebay for under $10. It takes about 30 minutes and you will need a pair of tweezers as well as some naphthalene to get the old glue/seals out there.
If its something mechanical there are lots of "for parts" bodies on
ebay that you can scrap for the parts you need. Generally a decent set of watch screwdrivers and some tweezers are all you need to get these cameras apart. Broken gears/cogs/levers are usually fairly obvious.
If its just a matter of old oil clogging things up you can tear down the body fairly easily and use naphthalene to thin the old oil out and replace any missing oil with watch part oil. I would advise applying the naptha with a syringe delicately, use a microfiber to keep it where it needs to be and a watch oil tool (really just a needle) to get any new oil on. >$20 worth of tools and solvents and some time.
But as many mention, there are lots of really good examples floating on the used market and it may just be in your best interest to replace it. If the camera has some kind of sentimental value or personal meaning then by all means fix it!
Regards
Dave