If anyone's interested, I just got a calculated 19.12 m2 out of a tub of Dulux "Once" Emulsion which claims 22 m2 coverage.
Which is pretty good, considering I was slapping it on under the mis-apprehension that the room was tiny (it is, but the calculated value based on actual measurements is in fact more than I thought).
Seems to work pretty well, onto magnolia anyway - I did go over the filled bits and pen marks with a primer coat of the same. Good result too in my daughter's now-exceedingly-pink bedroom :) Good even colour.
2 decorating jobs started and complete within a 10 day span - that's a record for me. Just got to put the shelf brackets back and oil the shelving and I get me a lab (well, home-office, but it's going to be full of computers, so it's a lab...)BTW - 2 product tips:
(And I'm not one to frequently praise B&Q products) - but B&Q's blue low-stick-easy-peel-even-after-days is actually bloody good. It did stop the paint dead in it's tracks (well, slight bleed onto skirting where it's lumpy, but pretty good nevertheless) - and it didn't pull all the paint of the ceiling like the last tape I used...
And this:
Good job I have a most excellent landlord who doesn't mind me doing stuff, though he's not seen the shade of pink (bedroom, not lab!), so that could change ;-\
Good night,
Timbo