Thanks - this is really great advice & very re-assuring! I just wanted to make sure I wasn't poisoning him, I guess. I know I should have changed gradually, but I really couldn't bring myself to buy the Go Cat, which is pretty pathetic, I realise, but there you go.

I'll persevere with the current diet for another couple of weeks, then try out the sensitive foods if there's no improvement - thanks so much for the links to those, which are a huge help.

Luckily, I have managed to "train" Lupin to poo outside in the mornings, so the process is not so bad for me ... I still have to watch, though, to check the consistency ... yuck!

Thanks again