Flying ex-LHR, not much has changed in terms of turn time between last year and this. But this year there is a persistent problem with late departures. The problem seems to be largely late arrivals but also the slower handling of re-doing everyone's seats when the 777 swaps to old configuration - an issue last year but seemingly a slower process this year. As a result, UA has gone from an on-time record that was better in the TATL market than BA and VS to one that is significantly worse AND UA schedules its flights as 15 - 20 minutes longer.