My friend, If you are applying for a career in ATC with NATS and you are successful in getting through the selection process then you will be signing yourself up as a mobile grade and THEY will determine where you work.
Realistically that could be anywhere in the UK from Aberdeen to Southampton. Although I am led believe there is some degree of preference from the student in terms their desired location, in most cases NATS will post you to the unit they require you to work at. That's all part of the deal I'm afraid!
P.s Leeds/Bradford Airport is a non-NATS ATC unit.
