KEH is generally well regarded. I think they are better for buying from vs selling to (I think they tend to lowball stuff people send in, even taking into account their need for a profit), so you should be okay. I have not personally purchased from them, but I do think I sold to them (ironically a film camera that I wish I still had) nearly 20 years ago.
I respect Lady Blackadder's dedication to her favorite camera, but if she would consider a Canon AE-1, my own personal favorite store and camera repair shop has two currently listed. These would have been CLAed and have a warranty with them and the store owner is great. But I'm also primarily a Nikon user, so I can't fault her for wanting a direct replacement. 🙂
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Thanks for the tip and link! Ironically, I have an AE-1 someone gave me (non-program though) that I never use. The battery door is cracked but otherwise it's in good condition and I believe it works fine. And I have plenty of FD lenses.
I offered her that one, BUT she really likes the ergonomics of the FM and prefers its simple meter. I would like to get a replacement that has been at least inspected, and preferably cleaned - I think it's certainly worth the extra cost. So I might wait and shop more to find an FM for sale at a camera store like the one you linked.