Speaking as a glider pilot/instructor local to the area of the accident, it has to be said that the Didcot - Abingdon area does have a LOT of traffic running north-south, especially on a good soaring day (which the day of the accident most definitely was) because of the airspace "squeeze" between the Brize zone and Benson etc.
Plus of course Didcot power station is a very handy navigation landmark/thermal source (the coalyards mostly). It is therefore an area in which an exceptionally good lookout is required by all parties.
It's not an area I would have personally chosen for AEF operations which might include rapid alterations in direction etc.
Are AEF pilots given a choice of where they operate or is it a question of "Smith go north of the airfield, Bloggs east, Brown west and Harris east so that you maintain separation from each other"?