Thank you! I forgot to say that I do not give him cold food, I let it stand for half an hour, or put a few drops of boiled water in - and now that I've got a microwave, I have tried to heat it up a bit in there.

I've just fed hím a bit of Specific Senior FGD - one at a time, he seemed to like that, but then, he'll probably eat anything that is opened 2 min. ago.

Let's hope the trip to the vet doesn't stress him out too much!