<< adjoining bath were the texture has flaked off. >>
Texture in a bathroom is poor practice. Remove and prime/paint with a quality
oil base made for bath areas. A rough nao roller could give you some orange
peel texture that is nice looking and practical.
<< because of a water leak- where it left a water stain. >>
Are you sure the leak repair is permanent? If so, remove old texture and redo
as you wish, retextured, plain paint, tin ceiling tiles, whatever.