Around 1963, Dryhurst and Belsen were the names of CAFU examiners to take note of. I much later flew with Belsen's son John when he first joined Caledonian from the RAF. John explained to me the rationale behind the rigid standards expected on all tests by his father and others, but I think by that stage I had already worked that one out......( I believe Dryhurst, died sadly, in a CAFU DH125 mishap at Luton )