Flew LHR JFK in J on 241 in 2015 on our 'minimoon' and asked at Club check-in (very politely) if there were availability for an F upgrade, having said that we were just two days married. The lady behind the desk said congratulations and that she would take a look and then said she was very sorry but there wasn't anything available.

Now whether it was a very polite fob-off or genuinely she was looking (she certainly seemed genuine), or she was looking but was then going to quote as opposed to offering a free upgrade, I don't know...

As we had no expectation of an upgrade it didn't really matter.