Hi, Kerry, I don't have brilliant advice for you but am sorry to hear you and your family are struggling so much. This must feel like a waking nightmare, especially at Christmas. I can well imagine how awful you feel.
From reading here on TP I can say that your mum is definitely NOT the only one to have this sort of reaction, including the escape attempts. This changes nothing, except maybe to reassure you just a bit, that you are not alone?
I agree with the advice to not bring her to your home for Christmas. The stairs, the change of environment, and the stimulus all sound like a bad combination to me (not that I'm an expert, but, just saying). Ten days isn't very long and if it I were in your position, I would be afraid that taking her out would re-set the clock on her settling, and also that taking her back to the care home after Christmas might be awful and upsetting for everyone.
I also want to say that, as awful as you feel, please try to remember that you are not a bad person, none of this is your fault, and you are not the enemy. You are doing your best to ensure your mum is safe, warm, fed, cared for, and looked after. The disease is the enemy, not you! This dementia cr@p has a lot to answer for.
Ellie, I'm sorry to hear you are in a similar situation. I like your strategy of reading through old papers, to find comfort and reassurance. I am also impressed that you are able to visit your mum when she is so awful to you. (When we moved my mother into her care home, I didn't visit her, at all [after the move in day] for almost two months.) Just to tell you a happy ending story, my mother suffered from crippling anxiety and panic attacks before she was in hospital/moved to the care home. Ten months later, her anxiety has virtually disappeared. While I know this is partly due to the doctors finding the right combination of medications for her, I think it's also being in the structured and safe environment of the care home. So please have some hope, that it could get better for you mum.