I do remember, however, an OCU conversion sortie which involved a high speed run in a Mk 1 without the use of the Mach Strut. Somewhere up at 45000 ft or above we began a shallow dive. At about M0.95, and with the aircraft pitching down furiously, my instructor said - "look out." Fresh from training, I did! Not that there was much to see (see earlier posts) - by which time we were very close to, or had actually exceeded M1.0!