From what I hear, arranging to visit the tower at LHR is very hard, a bit like trying to get into Fort Knox! You'll probably have a bit more luck with LTN or STN as you don't have to be granted airside clearance to visit them.
Thanks for the info, is that the same with Gatwick as I live closer to Gatwick and would be easier for me?
If anyone can help with contact numbers for Gatwick tower (if easier than LHR) or Swanwick it would be greatly appreciated.
Thanks!