Any question answered...

^I tried that, sanded the edges real carefully and used a tiny bit of filler to get it completely flat but it's still visible and looks shit. I used to be a plasterer, which oddly enough meant there was no way I could be arsed to skim it.

Either scrape all the paint off (PITA) or get the ceiling skimmed.

So if you removed all the loose stuff you can skim straight over paint?