i think i got really lucky.
many moons ago i had a rendezvous with a lady some 5-6 hours before a flight
what was planned was a good friend would meet me for dinner, then i would head off to LHR (takes 45 mins on tube and a good part of 30 mins for a cab).
after what it was a nice bottle for "tea" and some time, we passed out in bed and I (almost, woke up 30-45 mins before cutoff) overslept my flight (yes, i no-showed my friend's dinner. she drove all the way across london). since it was LHR HKG and they have multiple flights in the evening, so i figured i shall go to the airport anyways since they can put me on a later flight if they arent full (awards are flex tickets - i guess id pay if things come to the worst?)

Dont quite remember the details but i just about made the cut off - didnt matter much anyways, the flight was delayed for approx an hour.