Thanks guys. I did wonder if it was related to upper winds, but I thought a more direct routing (great circle) would have been the first consideration. But I guess if the favorable wind results in a shorter journey time despite longer routing, thet's the one to choose. We did descend to 28,000 feet at one point to avoid the worst of some turbulence - even at that level the light chop was nearly enough to spill my Champagne.
I was talking to a fellow flyer at the weekend about this, and he reminded me of the old days of piston transatlantic airliners. They used to employ'pressure pattern' flying (following favorable isobars), being at low enough altitude to be affected by high and low pressure systems.
And Concorde, of course, was so damned quick that the upper winds at 60,000 feet were not of significance and they flew the same tracks every day.
SSD
[Edited to thank Capt. Airclues for the link - but I'm afaraid those waypoints don't mean a lot to me. I recognise some (JFK, Merit) but is there a site that gives lat/long?]