This is a continuation of A Lesson in CS. If you haven't read that than this post won't make any sense at all.
So after getting annoyed they finally answered my simple question.
MOBILECO: You can activate it while in Canada if it's topped up but International Charges might apply since it's UK SIM abroad for now.
MOBILECO: If you turn it on before you leave Canada it'll be activated there & then. Your allowances will start then. The calls/text allowances are only for use in UK so you won't be able to use any of the allowances until in the UK. More info on how to get started with PAYG sims can be found at (link removed).
So basically, since activation involves the company texting you, it's not exactly recommended, but it can be done. :D
Lesson? Insults can work so long as they are not personal and derogatory. I insulted with hope and a withheld opinion of their service.