That sounds about right; Brize - Masirah was 15½ hours (with very little in the back).
I find it quite fascinating that G-HLFT is the one that has survived. She was originally XR365 "Hector" and was probably the most cantankerous of the fleet. She was known by all as "Silly Old Hector" (from the kids TV show) and the best advice was never to go flying unless her black nose was wet.
What used to fascinate me was that half of the 'B' Defects would disappear during a sector and then another half a dozen would come out of the woodwork before next landing!
I am totally fascinated by the reports that work is going on to get G-BEPS airborne again. She was the first Belfast to fly (apart from the prototype) bearing a civilian registration. From my logbook the date was 14 February 1978, the place was Manston and Heavylift hadn't even been invented!