i knew both Mike Randrupp and Walter Shirley though both are now deceased. Mike Randrupp was a test pilot for Napier and when that firm folded he was employed by BAC--later to become British Aerospace-- in a non flying capacity. Walter Shirley also transferred to BAe and worked as a Flight Test engineer on the MRCA (Tornado) programme. I was a Tornado test pilot in the 70's and 80's, later Chief Test Pilot. Neither flew on this programme. Walter once described the development programme for the twin Scorpion rocket programme flown using the Canberra. There was concern that the rocket flame path which extended under the Canberra belly would grow dangerously close to the skin as indicated airspeed reduced at high altitude. He devised a crude but effective way of checking the flame path. He fitted an array of silver solder bars protruding from the a/c belly and with a series of flights was able to observe, post flight, the pattern of the flame path as indicated by the material burnt away, and related this to the flight conditions they had set up.
I met Mike Randrupp in Saudi Arabia where he was managing the BAe operation at Rihad in the early 70's.