Thanks everyone - I went to bed last night very down and expecting to ring the vet today to get him in sooner than Thurs, as he spent all evening in the bathroom and barely touched his chicken. This morning, a brighter Tino who is scoffing his chicken like he hasn't eaten (well, sort of true), so he has a reprieve for the day, as he can cope with only eating chicken for a few days.
JS - obviously cats do get thin with age, but his is entirely health related, as his hyper-t is speeding up his metabolism and he isn't eating enough to keep up with it, he has already shown he can lose 400g in a week, and I suspect he has had another of those weeks.
Sue - sadly I have, my first ever cat. She started fitting in the early hours, and ended up on a drip at the emergency vet. We visited the day after, and she was still fitting when they took her off the morphine, so it was my choice to let her go or see if she had a chance, they did warn it was very slim - I let my neighbour talk me into giving her the chace, and she went an hour later alone, when she could have gone with me there - mind you, she didn't particularly like me, so whether she would have liked it or not I dont know (Her owner died and she had spent weeks outside cos her son didn't like cats, so she was a tad messed up)I think that is why I am so 'passionate' about being with them