Many thanx Wiggy for your helpful reply.
Journey out was some 10 hrs and IFE showed a headwind of about 50-70mph if I remember correctly.
However journey back was only 8.75 hours, tailwind of 100+ which was welcomed by all!
Also outward we reached 40,000 or poss higher, but return I don't recall exceeding 35,000 (but of course slept quite a bit!)