Richard Mckeown
Hi Judith. The black patch on the ceiling is probably an old damp issue or where mould spoors are growing on an area of poor ventilation, ie in a kitchen or shower area. The best bet would be to wipe down with bleach (and gloves) to remove the main spoors, then wipe clean with a mild detergent, and finally treat with a damp block/ stain paint which can be bought from most do it yourself places. The ceiling will finally need to be painted but this should eradicate the situation
