Three visits to the vet so far, and another one tomorrow, but I'm happy to report that this morning she ate on her own (two dishes of food) and is right now sitting up and taking notice.
She's half in and half out of her heated bed here, fast asleep. You can see the sheepskin covered steps I bought for her to climb up and down onto her chair so she doesn't 'jar' her joints jumping.
This has been such a worrying time, I hope she continues to improve, she is so loved !!