Okay so... Last night after sorting him out in yet another tub (attempting to cause as little stress as possible here...) because the last one was way too small, we decided to try and feed him.
He was on jumbo mice, as the store did say he wouldn't take rats. So we bought a couple of jumbo mice just in case and the store gave us a fluff too so we could try him on it. We tried him on the fluff straight away... and he took it first strike, gulped it down like he'd never tasted anything better!!!
Very happy. Proud much? Yes. I think so.