6500 feet for a VC 10, no problem , even at MLW 107, 500 kg ( if IRCC) even with only two reversers.
......and NO Beagle, BOAC instructors did NOT close the HP cocks for engine failure simulation, at least not in my time.
We learned the folly of that after the Meteor bloodbath at Driffied back in 50 s .
RW 23 at LHR was just about 6,500 feet.( yes I know it was used when the xwind on 29 was strong !)