For the past few years Brits have had an allocation of 5,350 visas. During the past couple of years, the visas have been released in batches (e.g. 2000, 2000 and 1350).
There has been no indication that the allocation volume will change for 2015, though there are suggestions that the work permit will be increase from 1 to 2 years. If that happens, then you will be able to get a single 2 year visa (as opposed to before, where you could get two 1 year visas).
IEC visas for Brits go incredibly quickly, but in the past couple of years the CIC have given dates and times for the release of the visas. You should keep a close watch on the website for any updates. There are various facebook pages (and other types) that you could subscribe to to get update notifications.
In order to apply, you will need an electronic scan of your passport as well a copy of your resume. The resume copy should be in the IEC format.
http://www.cic.gc.ca/english/information/applications/guides/IEC.asp#appA
You can work wherever you like in Canada; I had some doubts about Quebec, but I can't find any information to suggest that you can't.
You should pay close attention to the CIC webpage and get those two documents prepared in advance. It's not a bad idea to have your police certificate(s) ready in advance as well.