Hi bullivant,
Welcome to TP, but sorry that you are having difficulty getting good care for your grandfather...and sorry to hear he is suffering from this awful disease.
We are not allowed to post recommendations for specific organisations here, but I think people can pm information if needed.
Are you looking for full time live-in carers? My uncle has chosen this for my auntie in preference to moving her into a care home. It is working well for them and he says the cost is slightly less. His agency is not located near his home, but the live-in carers go all over the country. I think he has a rota of two ladies who work for 3 weeks each.
Otherwise I am afraid I can't help, but am sure there are others here who will come along soon.
Best wishes