We moved house recently and our first job was to repaint all walls. Upstairs in our conversion the previous owners painted plasterboard walls with satin paint, not a good paint either. Now everywhere there are peelings of paint coming off. Should I just try and paint over it, sand it down or strip all of the wall first? Do I use PVC or a special primer? I would like to do this properly, so any help out there I will consider to mend my walls.