Nokio,
I funded my own ADI recently after I was chopped by NATS and as some of the others have said, the colleges are really helpful at letting you know where vacancies arise. I think some airfields actually ask the college if there are any trainees which would be suitable, but cant say for sure.
When I finished my course the hard work began of trying to find employment however, in contrast to what goatface has said, I had a lot of interest from prospective airfields. I will stress though, that it is hard finding that job and you will have to be prepared to spend a lot of time and effort in searching and travelling around the country for visits/interviews.
Its an expensive option which focuses the mind, especially during summatives and exams, however I am one of about three people I know of who have taken this route post NATS, and there was also an ex blippy on my course and all of us have jobs as ATCOs.
Hope that helps