Thank you all, very helpful.
He has not had cat flu in last 5 years althouigh I vaguely remember a vet at some point saying that he may have had it in the past, something to do with one of his eyes, although I also think a vet said he had a minor heart murmor and yesterday the vet said he had no heart murmor.
It could be heating cos its gone warmer .
He was vacinnated against cat flu until 2 years ago when it was stopped cos of his seizures but as he was in vets overnight last week I wonder if he picked up something there!
So many bloomin options.
His bloods showed he might have a minor infection and he had a very slight temp, looks like I will be off to get the abs syringes on Monday unless it vanishes over weekend. I wasnt given them yesterday cos vet wanted to see if he improved after steriod injection and appetite stimulent.
Vet is closed until then unless its an emergency and dont think it is at present, will keep a good eye on him.