Thanks for that. Yeah, the image shows the tracks flown by some 118 aircraft. It doesn't show everything else that was happening at the time (e.g. departures/arrivals to Brize Norton and Lyneham).
There are also areas which have nothing like as many movements as that, and are far less busy than the surrounding class G which everything else is forced to use.
Interesting! Do you have these stats?
The whole purpose of controlled airspace is
to improve aviation safety by reducing the risk of midair collisions in areas of higher density air traffic operations. It is not there to squeeze this traffic into tighter corridors.