Not uncommon in Australia too. As a very ordinary General Australian speaker I use haitch (and therefore a, not an). I'm probably not 100% consistent in this. It's one of many words where Australian English permits two equally valid pronunciations (e.g. 'dance').

I do cringe when people insist on "an + h" where the h is in fact invariably pronounced, as in "an historic occasion". You only ever seem to hear this from Americans trying to sound educated, which makes me suspect it's affected, not organic. I doubt the person giving a speech on 'an historic occasion' would then go home and give his kid 'an history book'.