In the process of painting my bathroom walls from white to grey. After the first coat it has become apparent that the previous owner painted the bathroom door then opened it, leaving a little L shaped splodge of gloss/satin paint where the corner of the door hit the wall. Not noticed it before because everything was white. Now obviously my emulsion won't stick to the splodge.
Help! Do I have to sand down through two layers of paint to get rid of it or is there something magic I can paint over the top to make the emulsion stick?