Bolly, are you asking on behalf of yourself, or for someone else?
I don't wish to be rude, but any qualified atco would have a good idea of who is employing who at the moment.
If you're an ex cadet who has an aerodrome rating but didnt make through the area/approach course, then I'm afraid you've got lot's of competition. The majority of non NATS airfields are training there own atco's at the moment, but the very large majority of these trainees are existing staff, (atca's who have been in the pipeline for sometime etc.).
If you want to email me with some info' about your exact situation, perhaps I can point you in the right direction.
(The person to write to at SERCO is Sally Johnston).