Can't speak for the military birds. For what it's worth, on the Standard 1103s and the 1109 (to which spec the prototype, G-ARTA, was modified for airline service) Mmo was M0.86 (true) = M0.886 (indicated). I don't know Vd. On entry into service with BUA in 1964-65, they cruised them at Mmo, with the overspeed bell often ringing intermittently in gusty conditions. By 1971, as BCAL, we normally cruised at M0.835 (true). After the 1972 fuel crisis, we were down to M0.82.
The 1103 was a Standard VC10 with main-deck cargo door and what was referred to as a "super" wing, with Kuchemann (droop-snoot) wing tips, to enable cruise at up to FL430. (BOAC's Standards were limited to FL410.) Unlike the RAF transports, there was no APU, a dry fin, and the engines were as for the Standard VC10. The 1109 was similar to the 1103, but no cargo door.
G-ASIX, which had cracked its tailplane bullet in an upset over Mendoza in about 1972, was sold to the Sultan of Oman in 1974 as his personal jet. He donated her to the Brooklands Museum around 1989, where she can be visited. That cockpit...