You can add 935 LHR-LAX at 59% and 931 LHR-SFO at 51% on time to the list of shame. The latter used to fly on time regularly last year, so I'm not sure what's happened - I should imagine that the regular configuration changes haven't helped.

As to cancellations, my three trips on 935 this year have all been cancelled and 931 is running 1 out of 4 for cancellations.