Hi,
Just chipping in to say I'm over in Swinley often for a spot of mountain biking, as it's almost on my doorstep, and so have had a chance to follow the recent activity (hard not to miss it as a lot of the forest is closed off). As it's only the weekends when I'm there there's not much going on and what I've seen isn't much different to what's been seen already.
But anyway, my photos are available here if you're interested:
Flickr: tj.moore's Photostream
Certainly looks like the crane set up is either a flying stunt, or a high-wire tracking camera shot set up.
Did take a peek in a truck window and saw some kind of shooting sheet but there was nothing on it, except for the name Leavesden Studios.
p.s. Swinley is great for walking, cycling and more importantly mountain biking. Some of the best mountain bike single track and downhill in the south east is in this fantastic place!
Oh, and full marks to Warner for their commitment to the upkeep of the forest.
Cheers,
Tim (DeadKenny).