As for OP UG's...I was flying LON-WAS-LON a lot this time last year (pretty much ever weekend) and was regularly given an op-upgrades (arouns 3/4 flights) on the IAD-LHR flights when taking them, but was only ever in the front of the bus once flying LON-WAS. Smile sweetly at the check-in agent when you check-in. If you have any status with CO speak to the CO international concierge that should be hanging around the check-in area, and make yourself known.

Steve