Can you get her to a vet? It could be anything - even idney issues, so it's very difficult to know. Having had a stroke before, its understandable that you would think she's had another one, but it may not be that at all.
It sounds like you are doing everything to make her comfortable, and karma to you for that. Being on the Isle of Man, I'd imagine there would not be a whole lot of variety, vet wise - but a vet can consult with an Avian one if need be.
Best of luck! Keep us updated?