Argonautical's question is also one that has puzzled me a little for years.
Yes, I too know all about oceanic tracks, great circles and jetstreams etc.
I have flown literally hundreds of times between London and New York in the past 25 years. I have never knowingly flown outbound or inbound that far north. The most northerly tracks have tended to be over Northern Ireland and the Lake District. The majority (at least 90%) go no further north than Liverpool/Dublin and about half over south Wales/southern Ireland.
True, in earlier days before in-flight moving maps there would be some tracks I wouldn't know or recognize, but I do think a Lockerbie/Glasgow track to New York is unusual. I guess it was just a coincidence. Obviously more normal for flights further west in North America.