London underground music scene

I am a producer researching a documentary about the 'underground' music scene in London. I am in bad need of some contacts and a few ways into the scene - the film is being done by an American company for a music web tv station: fuze.tv. It will be a very small crew shooting hand held, running on the hoof with the whatever happens in front of the camera. They want to see what the scene is really like and the more full on the better!

This is their brief:

We aren't looking for established concert venues, but rather the empty buildings, warehouses and houses impromptu raves, concerts and jam sessions take place.

We're looking for illegal "free" parties and hope to document the scene and lifestyle of its participants as authentically as possible, so do you have connections or feel you can connect us with people with credibility in this scene?

Specifically, we'd like to contact an organizer and see how they select and set up a location. Connect with partygoers and see how they find a "free" party, and finally see where the night takes us.

they are hoping to shoot the weekend of the 17&18 May (or the following) and are hoping to combine something edgy, with maybe a bigger / organised event over the same weekend.

Any ideas for promoters / organisers / DJs / ways in?
If it is easier than typing, give me a time that works, a number and I will give you a ring,

Many thanks for any ideas, events or contacts!
contact me on aq.curiousape@gmail.com

Alex