Hello Sarah,
I too was a Nav Rad at Cottesmore at the time of your Dads death, though on 12B Sqn. I knew your dad quite well as we travelled into work together some times, I lived at Langham and he nearby. As I remember just before the accident he had had a car crash, not serious, hitting a cow!, but his car was badly damaged.
The accident was horrific, with as you have heard the two pilots getting out by the skin of their teeth. Mike Gillette moved over to our Squadron later as co-pilot.
Hope this helps a little.