Small painting job

I would always zin Zar solvent base Three coats. Then paint as normal Hope that’s helpful Gary.

I would give the area a light rub down with glass paper then apply one or two coats of dulux stain block then when dry give another light rub down and then one or two coats of your choice. All the best

Sand down to remove all loose flakes around affected area with a P120 Apply, Zinsser - Bulls Eye 123 - Primer / Sealer / Stain Killer The Blue can is what you need leave to dry - 60 / 120 minutes (let dry out perfectly) Slightly rub down and apply 2nd coat once perfectly dry - apply your ceiling paint job DONE that's what I'll DO

Zinsser b i n which is shellac base x1 coat followed by your choice paint or paper.

I would highly recommend zinsser , it’s very easy to apply and is recoat-able within 45 mins. You will probably need around 3 coats to fully block out all the stains , this can also be used on wood work to once fully dry you can apply your choice of paint to wall .