And yet, the council's response was...Thats a sinkhole!
Standard Auto Reply said:At this time, we do not feel that any action is necessary but appreciate that you were concerned enough to report this matter to us.
We will continue to monitor this location as part of our routine inspections and works will be carried out if required in the future
You hardly need a bivi, you could just lever one of those tyres off and sleep in that.