As it is, I ended up having to rebook for different date. This time, when I phoned in the agent recognised my accent and changed the country before doing the search. In doing so, she could no longer see anything less than W on the direct OSL-EWR route and tried rebooking a fare that was $300 per person more. I ended up cancelling the booking completely and rebooked onto the OSL-FRA-SFO-LAX route, making sure that I went for L to get the miles off LH. Not ideal, as it still cost more, and I'm now on a 747 from FRA-SFO. Hopefully, that will be compensated for by getting a GPU upgrade on the way back from SFO-FRA (the return was booked in W class as a gamble).

I can't grumble though, because it was still at least $200 cheaper than flying direct from London and the later departure from OSL means I can fly LHR-OSL that same morning instead of the night before.