Tengah Type, I don't think that dummies were dropped. The buffeting experienced whilst flying with the chute extended was considered to present excessive risk, we were told.
The VVSO who dictated that the VC10K should have a crew escape system paid a visit to 101 in the early days, although at the time I didn't know he'd been the one. On the jet, he asked me what I thought, so I gave him my frank views. 'Buff' was standing behind him giving me a "FFS shut up!" expression, so after the VVSO grunted "Well, I think the lives of you chaps happens to be very important", I agreed and said that concept was one thing, execution was another. If we were that important, then the aircraft should have been redesigned with all crew in M-B bang seats. At which he harrumphed and left; no doubt I had another 1369-limiting narrative comment that year.