Thank you everyone. Means a lot and I'm already missing him.
Susanne the vet mentioned Crystals in the very beginning as one cause. However, when he phoned back he said they found no crystals in the urine, he also mentioned the possibility of a stone but if it was that they've not found it. So nope I have no idea what it is and if it is crystals which form.
Thank you so much Gillian ...... he has a pouch per day split over 2 meals and a small amount of dry. He actually does drink a reasonable amount every day so it's not something I've ever been too concerned with - though that will now change. Unfortunately he won't eat raw, Memphis has never been a big eater and raw is just too much effort for him
At the moment I'm snuggled up with his favourite mousey