Sounds like you are now slowly moving forward. Can I ask specifically about the downstairs toilet issue. Does Gran not have a toilet in her annexe? If not, there is a quick and easy solution, a caravan style "Porta Potti". These are brilliant, my family were caravanners and used one regularly. For one lady, it would only need to be emptied about once a week. All the "product" is stored in a separate container which has a small quantity of special fluid added.
Just briefly for now (for a change - sorry, I know I run on!)....that all sounds actually much more positive! I'm glad you have some 'space away' from her. On the other hand, it's great your family want to give it 'one last go'.
Sorry you find the commode grim! Personally, I think they can be a godsend. My SIL needed one while she was waiting for her hip replacement, as their bathroom is up some steps and through two rooms .....'urgency' because a real issue when she was hobbling around pre-op.
Definitely get some carers in on a regular basis.
Re money - in principle fine that you need more. How will your mum react? (Or will you threaten to deposit Gran on her doorstep if she doesn't cooperate?)
I think respite care should be a priority however - what about over the Feb half term, so you can have a break while the kids are at home, have some (cheap) treats with them.
Cheers for now - you definitely sound less 'on your knees'! Great!