Thanks - 380 is something I hadn't considered.
Looking at the timetables both CX and QF leave around midnight for LHR. It feels a bit of a waste to get on a plane, eat a dinner so late and then to bed in F.
I wonder if a better option would be to take JL which leaves at 11am (NRT) enjoy the full service (if older sky sleeper solo seat) and then go to bed in London?
J