i used this paint watered down as the instructions said (although it
didnt really mix well with the water), looked like it went on ok, but
after having to chase some cables, ive noticed the paint peels off
like masking tape. its just like a film and coming off in huge bits.

can anyone advise as to what went wrong? i am happy to remove it all
and start again (comes off so easily with a scraper).

i did wait several weeks before i painted so the plaster had dried.