Thanks everyone for the support it means a lot. We had a nice walk at the beach this evening with fish and chips in the car, Jethro got a sausage so is a very happy dog. Cant say he isn't spoilt.
No news from Edinburgh, The message the vet was saying yesterday made it sound like this is the last option and not to get our hopes up of it working, and to consider the effects on his bone marrow. It wasn't our normal vet though as ours is on holiday. It sounds like they would like to be seeing an improvement either in levels or stability within a couple of months and ween off the steroids if they can. They still sound like aiming for a maintenance dose of one or the other drug is the plan if he takes to it.
Im still hopeful, husband on the other hand is needing a bit of a push to keep the hope up.