The badgers have dug a new latrine on the edge of the enclosure. Wild badgers mark the boundaries of their territories with latrines. When they were first installed in their new home some of their dung was scattered around to make them feel at home (not something suggested by Secret World, but it couldn't hardly do any harm, surely).
Newly recorded behaviour (seen often before with wild badgers) was one of the badgers scent marking the other and then checking the scent (it's how they recognise each other in the dark).
The playing is not just chasing, shoving and rolling but trying to grab each other's ears. It seems the trick is to roll one's opponent by the ear. It's how badgers fight -- with other badgers for territory.
Rolling by the ear
When badgers come out the first order of business is usually a good scratch and sometimes some social grooming. These badgers haven't been seen doing much mutual grooming and their scratching is fairly brief, perhaps as they don't yet have any badger fleas. This will likely change if and when they come into contact with wild badgers.
They appear to be in fine fettle and ready to go exploring when the fence is removed in the near future.