From what I remember when I asked I think that you can rent it either tuesdsay, wednesday or thursday. It costs nothing to get just the back room and if you get enough people in they will close it to the public. However if you want the main room you have to garauntee £1000 business at the bar, although the bloke I spoke to didn't explain if you had to put down a deposit or something else.
its not really a back room though.....its just at the back, same sound system etc. I was playing there last tuesday, and the guy that hired it got the whole place for free...didnt have to guarantee any bar money or anything like that. Stereo isnt really a dancing place as such as there are seats everywhere, they are fussy on music, so i'll be suprised if they allow trance....they don't allow hip hop or RnB...usually house, inde on a thursday. Incidently you cant hire it on Thursdays - its Stonelove.
you can get it on Tuesdays Revel, I doubt they will let you play trance. I have a friend who is the back bar manager, I can ask for you if you like >?