Thanks Vinn. Simple answer is that I don't have any PVA but do have APD as I used it when tiling the bathroom, hence why I wondered if it would be ok to use.
Hope this isn't a silly question. I have a small wall which had wallpaper on it. I've removed the wallpaper and the plaster looks a little scruffy. It's been painted and everything looks sound. I've given it a good sanding to get anything loose off and I'm ready to give it a new coat of plaster...