I've been using this one - or something very similar - for someone with MND, (not my Dad who is the one with dementia). The hoist was ordered by an OT.
https://www.completecareshop.co.uk/...gs/oxford-stand-aids/oxford-journey-stand-aid
One care company insists it needs two people, another has risk assessed and is OK with single operation.
I use it on my own to transfer from wheelchair to loo and back again. Quite honestly, the floor surface makes the biggest difference to ease of use - on hard flooring (which it is in the bathroom) it's fine - on carpet, it's harder work. But for toileting, it makes for easy access to the necessary bits!
One caution I'd make though, is your mum's ability to hold the handles as these give extra stability when transferring. The person I use it for, can now no longer hold long enough with one of her hands, and the arm slides off. The transfer is still do-able but needs more care from me when positioning. I suspect we'll be moving to a different hoist soon.
On a separate note - elsewhere you've asked about catheters. The person with MND was getting ever more distressed with the difficulties in getting to the loo in time, as mobility was lost. She herself opted to be catheterised and has been now for about 5 months. It brought her much needed peace of mind - but hasn't been without difficulties. She had a bad run of blockages - but has great support from the district nursing team, who turn up pretty quickly when there are issues. What became apparent was that constipation was having a bad effect on the catheter - it seemed to encourage a biofilm to develop which then blocked the inner bit of the catheter. Keeping on top of the constipation with daily lactulose has led to a marked decrease in catheter issues.
In your mum's case, I can see how a catheter would help both you and her - no sitting in damp pads until a carer arrives to help you change, and the reduction in the need to move her, would result in less pain and distress for mum and reduce your need to do transfers. All you have to do is empty the bag when needed. It's a cinch. At nighttime the carers connect it to a stand, but during the day it's worn against the leg.
My learning curve on mobility issues has been over the last year or so and continues relentlessly on- I really feel for you having to deal with similar issues but in a much shorter time frame. All power to you!