That's about right for the inbounds from Tokyo, Hong Kong and Alaska as the shortest route from Tokyo to the UK and North Europe is a great circle track which takes you across Siberia, way up into the polar regions coasting out of Russia East of Archangel, around the Northern Cape and down across the North Sea or the East of Scotland. By that time, you'd be up at 36,000 to 38,000 feet or higher (depending on type). Aircraft will contrail from above 29,000 feet or so depending on the atmospherics of the day.
Stockholms, Gothenburgs etc tend to route across South Norway and North Denmark crossing the UK a bit South of the Lothians. The other possible would be outbounds from Scandinavia heading to the Caribbean on Mid-Atlantic routes. They'd tend to head for the Lands End and Southern Irish areas, depending on the winds across the Atlantic, before coasting out.