Thanks everyone, your messages really helped.
He's gone. We had him pts as he was no better today, and did just seem to be hanging on by a thread, so it was cruel to keep him with us for what could only have been a few hours.
He had kisses and cuddles goodbye from us both, and at the very last kiss, he put his little front paw up to my lip, as though to say "It's okay" and then I passed him to the vet, before bursting into floods of tears
And yes, I know I'm anthropomorphising, but I simply don't care, I'm sure that gesture was his way of saying goodbye.
Thanks again
Teresa x