Anyone moved their family to Alberta from England?

You neglected to mention where you live in the UK: rural, urban, sub-urban? If you want to live in a log cabin in the Rockies (I'm imagining soaring tors, pine trees and babbling streams is what you're looking for.) you'll be a couple hours outside of Calgary. I did a quick check for log cabins on the national real estate site and they seem to be few and far between. (I think your budget is okay, if you stay in Alberta.) Mortgage lending rules are quite strict in Canada, so you would have to be able to prove sufficient income to support the mortgage.

Each region of Canada is different, not just environmentally, but culturally. Outside of Calgary, the political climate is VERY conservative (I'm speaking in broad brush strokes here), religion is a focus. Homogeneousness is fairly common in the smaller towns of most Canadian provinces. This might or might not work for you. I, personally, would find it difficult to live outside of Calgary, just from a political point of view. I have family members who love it.

Logging: most logging is done by larger companies and would require long stretches away from house and family. Logging camps are set up in the wide swaths of forest throughout British Columbia, Alberta and other provinces. You might need to be in camp for several weeks straight. Much lumber processing is taken care of in other countries. (I sometimes think that Canada would do well to focus on secondary industry to help the economy.) It's also incredibly hard work and dangerous, even with all the technological advances. As environmental movements grow and the pine beetle infestation increases, I imagine that the industry will wane. We're in the middle of a soft wood lumber dispute with the USA, our major trading partner. You might want to consider looking into tourism related fields (one of Canada's largest job sectors) that will take you out into the beautiful wilderness, but let you sleep in your own bed most of the time. You might have to fight it out with Aussies and Kiwis to get a job, as they love being in the Rockies, too. There are many websites that show you what jobs are currently available, to give you an idea of what might be possible.

Pediatric nurses would likely have a lot of opportunity in the bigger cities in Canada. How your wife's degrees transfer over is another question. This could likely be easily answered by the Canadian Nurses Association or the Ministry of Health.

Living anywhere near the Rocky mountains means lots of snow and cold. On the east side you are exposed to Arctic winds and temperatures can drop to -50C with the wind chill. (Not an average, but it's been colder.) On the upside, you also get winter Chinooks, that bring warm winds up from the desert in the USA. I've been in -35C and it's really not that pleasant. All that being said the Rockies are stunning and I marvel every time I drive through them and life in Canada is fairly incredible.

I know that doesn't answer a lot of your questions, so I'm sorry for that. Hope this helps a little.