The UK has always been quite liberal with 5th freedom rights.
I believe Air India, Kuwait and Cathay Pacific (although CX never used them) have rights to fly to New York from UK.
Singapore does Manchester - Houston.
Hainan did Edinburgh - Dublin.
Part of the attraction for carriers operating 5th freedom routes is if there is a need for a stopover or it allows poorly loaded routes to be sustained by picking up more pax. Not many routes need stopovers now and the UK is a booming market so fewer stops are needed.