Arrrgh- just heard from the vets - I opted to have pre op bloods done and they have came back lypemic(?) which I think means even though I starved him from 7 last night there is still food affecting the blood result ? So I could have bought him home and starved him 18 hours and then had the bloods done again or go ahead with the op which the vet was happy to do - so I chose to go ahead today as starving him then taking him back would have stressed him out even more - hope I made the right choice!!