I really don't think they are doing it deliberately Brutal.
If they have just been launched on a SAR shout they will have far more things to think about than whose house they are flying over.
The vital thing is to get to the job ASAP so wasting time climbing to height isn't a priority.
Transiting across London with the very high population density is hardly comparable to flying over rural areas and if an S92 was operating regularly there, then people might have something to complain about.
I have landed at night in several London parks taking critically ill people to hospitals in a SAR Sea King over the years - and generated plenty of noise complaints doing so - sometimes you just have to suck it up or do you complain every time an ambulance goes past your house with blues and twos going?