Realistically you can not expect to remain north of the border. The majority of ATCOs will be posted to Swanwick and you should expect that, with anything further north as a bonus. I suspect you'll find plenty of ATCOs, who were dragged kicking and screaming north of the border, but wherever you end up most people become accustomed to where the get posted and don't want to move (moving to the unit of your choice can be easier after first validation, but usually only if it suits the company).