Yes, I took JL 3 recently and I am about to take this flight in a couple of days as well.

The only lounge access is Greenwich Lounge, as Soho (and Chelsea, which seems only applicable to qualified AA and BA passengers) are closed at 10:30 PM. The good news is that the terminal and lounge is not too busy compared to the majority of transatlantic flights departing at earlier times. I think it’s JL, CX, and a few BA/AA passengers left, which the latter’s flights leave by 11 PM.