<<July load factor of 163 is pretty rubbish though for LHRIAD>>
Really?! And what do you think the "load factor" was?
The LH BA 763 config (3 class) is ~178 I think. If UA has a similalr config, then a pretty good load factor I'd say... And for yield, far more importantly to know where those 163 were sitting (or rather paid to sit).
Maybe that is why UA had a 763 on the early LHR-IAD - good commercial planning offering some of their PAX an early flight option, with larger ac (777) on the busier later flights.
NoD