I would be nervous of using most things on leather, but what about trying a good leather cleaner or leather polish. I just googled leather cleaners and came up with a few websites specialising in leather care. You could even email/ring for their advice. At least products meant for leather will not do any further damage and will hopefully mask any smell or wee to stop her going back there again.

Thanks all, will go get a leather specific cleaner today.

Seren (the cat who wees) is an ex farm cat, but was 7 weeks when we got her and had been born and brought up in their kitchen, so not feral as such.

Like I said, she was fine for ages, and then Steve stayed the night (my fault, neighbours had locked him out and it was a thunderstorm, he had come in looking for shelter and i let him stay).

Really hoping the behaviourist can pick something up when she comes and we can sort it. I dont want to spend the next 15+ years with this!