The One-Eleven did seem to regularly handle sectors of that duration. The short 300/400 aircraft were fractionally better than the 500. There was a percentage that needed to stop en route, the calculations on likelihood must have been made. LGW to The Canaries is a comparable length, and against the prevailing wind, but some, Laker in particular, ran it for years. Bear in mind that the holiday flights, although full pax, unlike schedules had effectively no cargo.