Tesco Student Transfer 2016

I'm been working in a Tesco Call Centre in Scotland while at Uni, I'm moving back To Northern Ireland for the summer and am trying to get transferred. The store I want to move to has vacancies but they aren't public any more (not on the Tesco Careers site) as they are currently interviewing/hiring. I have spoke to a manager at the store about it and she says it is possible I just have to go through the "Student Transfer Service" and that colleagues that work there currently do it all the time. Problem is that's all the information she can give me, she doesn't know how the Student Transfer Service works from the Student end and neither does my current employer. Does anyone know how I am supposed to do it?