[Studio25]

Apparently, we're both correct - but my reasoning was wrong, so that makes it just as bad as being completely wrong. Apparently, it's all down to pronunciation, so some words (like history and euphemism) can sometimes use "an" even though they are usually pronounced with a consonant to start.

Thanks for putting me right. It also means there are a bunch of other times where I've been messing it up with regard to abbreviations and acronyms...