Big Talk with Mum went well. She was worried about some of the same things I was and was relieved I've found an option that will work better. Now I just need to make sure there are no major objections from my sister (which I am not anticipating) and we can start actually putting future plans in to place.

It will be a relief getting this all sorted. Having older parents is a double worry, both the direct worry about health problems etc. and also the worry that you don't have the power/authority to actually do anything to help prevent problems, but will be suddenly put into the position of trying to sort everything out in the middle of a crisis if something goes wrong.