That sounds painful @Bellebe, I hope they manage to sort it for you.
I’ve had a couple of 30min ops under a general in recent years. For each one I’ve kept my pump on and agreed that I’d aim to be about an 8 with no active insulin prior to the op (I suggested this approach, they weren’t coming up with anything other than a sliding scale). I’m not sure how long an op they’d be happy with this approach for.
Do you know if the pump is the problem, or if they just refuse to do any diabetic as a day case? If the pump is the problem you could always try a bit of basic education – personally I can’t see any reason other than ignorance why you’d operate on someone on MDI as a day case but not someone on a pump. Or if they’d be comfortable doing you as a day case if you were on MDI, you could choose to go back onto MDI yourself for a couple of days. That does seem like a huge step backwards though.
Re staying in until you’re stable – I’ve discharged myself a couple of times when I’ve been comfortable that the only issue keeping me in was diabetes and that was something I could sort perfectly well at home rather than in hospital. You just need to sign a form to confirm that you understand you’re a foolish and irresponsible patient who has chosen to ignore the doctors who obviously know best.