QF had a small fleet of early HS125s for pilot training back in the late 60s/early 70s. My father flew them a bit - wasn't impressed with them at all.
Sorry, haven't been paying attention.........
HS-125 VH-ECF and VH-ECE. They had several modifications to make their handling approximate that of the 707 under certain conditions. The rudder bias system was provided with an adjustment so that it could be made to simulate the foot-force required in a 707 with one or two engines out. The Qantas HS-125 also incorporated the artificial horizon and the Collins navigation system from the 707, but otherwise it was a standard HS-125.
They were also used for US aircraft repair flights, carrying LAME.
DCA also had a number of the earlier DH-125 varients, one of which VH-CAO landed wheels up 24JAN67 at Avalon, Vic.