Originally Posted by
aceman
So, how bad is it going to be?? Are vegas loads usually high? Any luck with those £499 C upgrades on the day?
Two class upgrades are rare, rarer still on a discount offer. Sounds like you're in a discount economy bucket too - if you're getting the 'fare un-upgradeable' message.
I've done WT LHR-SFO - a similar time/distance - a couple of times. It's pretty miserable, but then all 9hr Y flights are.
You might be lucky and be able to get a £179/£189 upgrade to WT+ at the airport. I've no experience of doing longhaul from LGW, but it's pretty frequently offered at LHR. Just ask at the check-in desk.