Hi,
I did work experience after my GCSE's, firstly at a maintenance base in ym village (lasham) with a company called ATC, spent a week in overalls climbing all over a variety of aircraft and enjoyed being the only girl in a hangar of 400 men!!
After that i managed to wangle my way to the ATC control tower at LHR, somehow my mum had contacts and spent a week talking aircraft down and up using prompt cards that the controllers had given me. I really don't think something like that would be possible now due to security but if you could get yourself into the new tower it would be something. I'll see if i can find the name of the chief controller that got me the place and i'll let you know.