Ah yes, those screened-off front seat VIP fits! I suspect they might always have been in occasional use but, with the demise of 216 Sqn's Comets in the mid-70s, they became increasingly common, both East and Westbound. Their existence could make life awkward for the Cabin Crew when senior personages, not quite so senior as the chap in front, took offence at a difference in treatment accorded to them. They were sufficiently frequent in the later-70s that no attempt could be made to ensure a 'VIP crew' flew every leg of a HK slip, say, as that would have been quite impractical from a scheduling point of view. Proper VVIP/VIP flights were those scheduled as such and given a 1000-series task number.