Jax, you really need to discuss this with the home. As Witzend says, a person who forgets where or how to go needs to be 'toileted' - that means guided to the loo and watched to make sure they have pants down, are sitting down, and may need wiping or washing hands prompts etc. Doing this drill also helps the person realise where the loo is, as does keeping the door to it open. Sometimes if a door is closed a person simply doesn't see that it is a door. It must have been distressing for both of you that she poo-ed on the bed but there is help.
Re the original question, I was self funding and am now asking for council help as Mum is under the £23k mark now. I have offered to pay a top up, but not as much as they want to meet the big difference between the council's standard amount and what the care home charges. As part of the process, they put Mum's care 'out to tender' and another care home has offered to take her for less than the cost of her current one.
However I will argue, very strongly, that she cannot be moved at 97. Councils do have the flexibility to pay higher fees if they think it is appropriate to maintain someone in a more expensive home and they can also try negotiating with the home for a reduced fee, plus negotiating with relatives over top up fees. So there is flexibility but you will have to jump through quite a few stressful hoops plus put forward a good case for why your Mum shouldn't be moved. Interestingly someone at the home told me this year is quite a good one for negotiating fees as there were so many winter flu deaths that most of them have more vacancies than usual, so off the record the homes themselves may be more willing to negotiate in that situation.
I do feel for you, it is a worry but it isn't set in stone, a lot depends on the state of the resident at the time they cease self funding.