11th May 2013 12:20 Start by stop prating about - grow a pair and just ask the dude outright. If he was in the service he would appreciate the frankness.
He did:
10th May 2013, 23:55 Evening gents
Update: Our mystery man was confronted and now admits that he was UAS and the Hawk stick time was back seat and once only (apparently, it was the ride of a lifetime...)
I also (subtly) checked colleagues plus the on-file CV - no inflated RAF claims, so no risk to the wider project.
Our hero is chastened and knows that he is under scrutiny. Case closed.
Thank you all for your kind advice and PMs.
