Hi Tiger Tim,
I was a FJ mate and moved over to Canada just over 3 years ago.
Within 6 months of stepping of the plane in Vancouver I had a multi Job. It was a **** one but 12 months later and some non centerline time in the Book I was in the Sim for a biz Jet.
As for airline work the above posts sum it up , but this is not Europe ,aviation is very diverse in North america.
As an ex mil pilot you will find some are scared of you (dont ask me why) and others except are diverse experance as an asset to the operation in respect to a low total time(for me as FJ anyway).
The Canadian Mil seems in more of a mess than in England (although S.H.A.R has put an new edge on that one).And you will have to be a citizen even if you did want back in .
Immigration is an issue you would have to address before crossing the pond.
Coversion is a piece of cake from a UK ATPL .I had it done in 4 weeks , but it was another 4 before I actualy had the ticket in hand!!!!
Good luck and its great in Canada