Saw the 'reveal' 2 days ago. So they've made it public and yesterday, security personnel flushed those on the surface and in the trees etc., out of the site. How long will they be able to stay down there. No doubt they have a food stash and drinks down there, but what goes in must come out!
Then there's the air quality, the CO2 level will rise quickly with no replacement, and that's before the possibility of foul air seeping in (of which London clay contains much even before the subterranean perforations of the last 200 years). Drop a wired comms line in there so that they can talk to the police and screen the 'shed' over the entrance to prevent them using any mobile phones that might just work at that depth.