Firstly - many people join NATS after having a year travelling or studing a course in Medieval Embroidery - a lot of plane spotters make it but there are many good controllers who never had an interest in aviation till they joined NATS. Like the chap said above it is all down to how you "spin" it at interview.
Second - about postings: very dodgy to compare UK to Canada. Canada is a continent, UK is a tiny Island... I agree with the geezer who says you "put up or shut up" about it - I'd understand if you were being posted to Bagdad but Aberdeen is not a bad place... it's not about location, its about attitude - if you go to a place and make the most of it, chances are that you will get a lot out of it.