Not being really British, the first time I got some Yorkshire pudding a few years back, I thought it was a nice desert (mind you as a first year student getting to the UK and wondering what's edible) only to find out that you couldn't just eat it raw and there wasn't any pudding in it per se. I suppose the British do not define pudding the same way continental Europeans do
There's nothing stopping you having Yorkshire pudding as a pudding. It is, after all, a close relation of the pancake. Cold Yorkshire pudding with sugar and butter or lemon on is nice.

As for cooking, IMHO the truly essential thing is to get that pan smokin' before you pour the batter in. I don't know about slow cooking after that, I leave it in with the roast at about 180C (fan oven, call it 200 for an ordinary one) for about 30 mins. Seems to work.

Mind you, I wouldn't claim to be a ninja of the Yorkshire pudding, merely a journeyman. I know my place, being a soft southerner and all.