BA generally fly a standard profile regardless of published noise abatement, so I presume their perf department liaises with the appropriate aerodrome or gedulatory authorities to aggree the deviation from published procedure.
Certainly when I went from flying an RJ around europe for Cityflyer, we used the published profiles, with a wide variety of thrust reduction and acceleration schedules. Assimilated by BA and retrained to fly the 737, I then went back to the same airfields and ignored the local profiles at all of them.
pb