Hello
I posted here in December about my rescue cat who went missing after six hours and who we successfully trapped after three weeks, only to discover he had turned semi feral...
www.mumsnet.com/Talk/the_litter_tray/2520618-Missing-cat-returned-very-stressed?pg=3&order=
I thought I would update you all that we took him to the vets three months after we got him back (he was still hissing at us and hiding at this point) about an eye problem, which turned out to be fine. However, they said he was also flea infested and would need neutering. Which was strange we thought, as the cats protection had said he was neutered... To cut a long story short it turned out we had rescued the wrong cat! Ironically an almost identical cat had stepped into the trap that night and we didn't twig 
The vet nurse was a CP league fosterer and took pity on us (given that we were getting nowhere with the semi feral version of our cat) and he ended up with the cats protection league main coordinator lady, who took three weeks to tame him (he was also neutered). Last week she sent me photos of him all cuddled to his new owner on the sofa 
Meanwhile I was newly distressed that my poor rescue cat was still lost and started putting out food for him (steaming salmon at midnight again...). A week later we spotted him coming for the food! So we borrowed another trap and this time DEFINITELY got the right cat. I was well nervous about letting him our after the frenzied curtain hanging ordeal previously but he just strolled out like nothing had happened and came straight over for a stroke. He is currently on my bed snoring as I type this. Goodness knows where he was for four months... I think he must have been stealing food from cat flaps because he looks none the worse for it. The vet said he definitely hadnt been surviving on mice all that time!
Anyway, thought you'd like to know that he is back and that captain curtain cat is finally out of hiding! Thanks again for all your advice.