I got also got through the selection process by doing pretty much the same as Vectorline. I had no aviation background at all and the preparation I did for the interviews/tests was limited to learning the information I had been sent by NATS( this wasn't because I couldn't be bothered to do anything else, merely that I thought that was all they were expecting you to know).
I understand people wanting to be as prepared as possible, however it just shows that as long as you have learnt the info they send, it is possible to pass with that
