I heard about the incident. It also appears that the Air Traffic Manager is on the UK Joint Airprox Board. So it looks to me that the Investigators of incidents are not reporting such events at their own units. Sounds to me like a case of "I better not report that one as it affects me and my position and status in the community". Not like "I'd better report this one as I am a professional and it would not look good that a member of the airprox board was not reporting incidents as we are supposed to do".