I recently had my wall & a patch of the ceiling plastered & waited until it was dry to mist coat. As I was applying the mist coat on the wall most of it went on fine but for the two sides (the larger patches in the pics) where it flaked off so I scraped all the loose bits off. Also when painting the final coat on the ceiling a little patch has come off there as you can see in the last pic. What should I do as the ceiling has now been painted with the final coat, the wall has only had a mist coat?