Well, I am sorry that nobody has bothered to reply. After the 11th September it has been difficult to arrange visits due to the increased security. If I may make a suggestion, this is the perfect time to prepare for that first interview for a job as sure as eggs is eggs, somebody will say to you prove that you are keen on being a controller. Well it ain't no good saying that you saw a film once and did a visit once to a tower, you need better ammunition as you will be one of many chasing that job, you need to stand out. If you aren't yet in the air cadets or air training corps, try it out, it doesn't cost anything during the initial probationary period, I got a private pilot's licence out of it before I had a driving licence. Believe me you need something special to be successful in the initial paper sift of application forms in order to progress to the test and interview stage. Bear in mind that the interview panel are trying to make your interview successful. They're not out to cheat or trick you.
For visits, maybe a nice letter to a local airfield would be a good start. Try out the small ones as they probably have the time and will be more open to visits.
Good luck