Thanks peeps!
Unfortunately it's not over yet
As I was leaving my house earlier and about to put my note through her door, Chavette was just leaving hers, so she had no option but to speak to me. I told her what had happened, and suddenly she brought her ex-partner, Chav, into it. She said 'Chav's not going to be very happy about that, he wants Roxy back'. Now she has told me several times that Chav is dying of cancer, although like everything else that comes out of her mouth it's probably not true. He seemed pretty healthy to me when he came to collect his daughter to live with him yesterday, although I could be mistaken, of course. And she has never, at any point, suggested that Roxy was Chav's cat. What I do know about Roxy is that they got her off one of my other neighbours (let's call her Scrounger) because she was 'attacking her kids'. So anyway, I said to her that if I'd known Roxy was Chav's cat, I would have spoken to him, not Chavette. I also pointed out to her that, sad as it is, it wouldn't be fair to move Roxy to Chav's flat when he's only got a few months to live. I asked her what would happen to Roxy after that and she said 'oh, we'd sort that out at the time'. I said it wasn't fair on Roxy for her to have to move from pillar to post all the time.
Then the truth reared its ugly head. Chavette reiterated that Chav would be angry if he didn't get Roxy back as 'he paid 70 quid for her'. I said 'nobody pays £70 for a cat!' and she said, 'well Scrounger said she was Persian' and I said she's not persian, she's no more persian than I am! Anyway, the short and long of it is, she wants money for Roxy
I just said that she should speak to Chav about it, and that in the meantime I'd talk to the foster lady, but I didn't know if there'd be any way to get Chav reimbursed for his (mythical) outlay, and even if there was, it wouldn't be £70! To which she replied, 'oh I don't expect that much'.
So it's all about the money
I suppose she realised that she wasn't going to get any money for the kittens, and decided she'd have money for Roxy instead. The thing is, before she'd told me that Chav wanted one of the kittens when it was born, and now she's saying he doesn't want one of the kittens, he wants Roxy. It'll all a pack of lies, and I'd pretty much ignore if I wasn't so worried that she might try to take it out on me (probably through my cats).
I'll phone the foster lady later and explain the situation, but I don't think there's anything she can do, and I wouldn't expect her to. I've thought about it and might say to Chavette that sure, she can have some money for Roxy, if she or Chav can provide proof of ownership, because pedigree cats always have documentation, don't they? I don't know - I'm at my wits' end.