Oh I totally agree that when you find a good one they can be a real treasure. I found a great SW but she got nobbled by the nasty SW we had last and I think the OT we had in the end wouldn't have been so bad if she hadn't been programmed by the nasty SW into singing from the same hymnsheet and taking whatever had been fed to her by the SW. Once I was dealing with her alone we began to almost get on but I was on my guard after everything I'd gone through with the pair of them.
There is an anti slip mat that can go on some things that might help stop your mum's feet from slipping. I'd even consider one of those rubbery things that get put on trays to stop plates shifting about if you thought that would do the trick.
I can understand not wanting to use a hoist unless a real last resort. I have seen people in hospital and in my mums nursing home really hating being hoisted, one lashing out because she was so scared. Bad enough without dementia but worse with.
I don't know the rotunda but can a new one be bought? Or a secondhand one? If you have your own I guess they cannot stop you using it.
Can you check whether the SW and OT are really qualified. THe HCPC is on the internet and individual names can be checked. They both sound very unprofessional!
It is so unfair - I was at loggerheads with the system whilst my mum was in hospital 18 months ago and it is ridiculous that you become the "baddie" after all you have done. I hope you have some answers on TP from people who are hoisting or have found alternatives. Good luck!