In the interests of fairness, radar recordings from the Prestwick ATC Centre will have been held and stored, SOP for any fatal accident, so any data would not be a fleeting memory but presumably can be checked on replay.
I was a military controller at Prestwick at the time of the crash, one of my friends was the controller on duty at the time.
He heard nothing on the radio, the radio replay showed a single call from the Chinook, obviously missed by the controller (although the books do say to call 3 times before assuming a unit is closed).
I personally videotaped the radar replay for the BOI. Well what there was to see, which was nothing. Radars available to Prestwick Control centre are many and various but the nearest in this instance were at Tiree and Lowther Hill.
I do not have a fleeting memory of this incident, it is so unusual as to be very clear in my mind, only the 2nd time I videotaped an incident.
NATS and the RAF are joint and integrated, there would be no reason for NATS to withold any data.
AFAIK the radar tape was impounded until such time as the BOI etc. handed it back. The video I made was sent to the BOI and they presumably still have it.
Brian is aware of this from a PM to him a couple of years ago at least.
BD