Seem to recall it was about 15h 6m. The a/c flew in pairs and if memory serves, the two pilots were Harry Davidson and John Walmesley.
The non-stop was only done the once, and thereafter the journey was broken at either Dubai or Masirah. The legs were about 7.5-8 hrs.
First refuelling was overhead Coningsby to prove the system. Subsequent plugs were just north of Nice, overhead Malta, 200 west of Cyprus, Lake Van and then land. Continuing east, plugs were around Masirah, 500 east of Masirah, 500 west of Gan, 500 east of Gan and finally about 1.5 hrs before Tengah and the cold Tigers.
Needless to say, this was an epic planning exercise, particularly for the tankers of 55 and 57 Sqns who were prepositioning and highly critical in terms of performance out of the hot airfields. Mk I Victors were entertaining to watch as they took off out of Masirah. It took tankers to refuel tankers to get in position with enough fuel for us. Still, it was all good practice for the Falklands. It was only in later years I learned about Perf A.
I recall being led on the Dubai-Tengah leg by the CO who's Nav, aptly nick-named Pathfinder, was determined to veer well off to the north of track convinced of his navigational skills. Calls of "Close it up" from the leader were ignored. (My back seater was quite sharp). Eventually, they disappeared from sight. Some time later, we picked up the tanker on the Tacan air-to-air and duly RV'd for a prod. The Boss turned up a little later and took on more than 22000 lbs. Since the total capacity was little more than that, it can be assumed that his guages before plugging in did not make a pretty sight. It was only in later years that I learned about ETOPS.