I apologise if this has been asked before, as I just skimmed through the pages, but in the British editions of the books are the abbreviations spelled with periods like they are in the Canadian editions (the only copies I have) or without?
SPEW or S.P.E.W
NEWTs or N.E.W.T.s
OWLS or O.W.L.s
I've also seen it spelled S.P.E.W. with a period at the end, even though the abbreviation wasn't placed at the end of the sentence.
Lia, it really depends which issues of the book you've got, and which book. In my hardback edition of OOTP, McGonagall talks about NEWTs and OWLs, butin my paperback of GoF, Ron says the twins did badly in their O.W.L.s.
It's possible that when they're using the fullstops, they are saying the letters out loud, so Hermione is more likely to say S-P-E-W whereas Ron and Harry would always call it Spew.
There's no definitive answer except to say be consistent.
Thanks, Carole. I knew the editors were inconsistent with a lot of things, I just wasn't sure about the British editions. Lol.