She left the series in 2005, with the death of her character.
Nana Moon should not be mistaken for Grammy Moon, the paternal grandmother of Daphne Moon Crane of 'Frasier'; two different women entirely.
But it could be that Granny Moon and Nana Moon were related by marriage. Perhaps they married the Brothers Moon and thus gave us a theoretical link between 'Frasier' and 'EastEnders'.
At any rate, my condolences to the Braid family and those who knew her and to her many fans. As Red Skelton would say, "May God bless....."