I think you'll find that 3,000' AAL is the maximum clean up altitude in UK airspace. 800' to 1,000' is the standard thrust reduction and acceleration. Noise abatement is based on track and not altitude...
Actually, I believe most carriers use an NADP 1 profile (the former ICAO A departure profile) in the UK and hold off cleaning up the flaps until 3000 AGL.
Does your outfit do something else?
From a Boeing article on the subject, emphasis mine:
These simplified profiles are based on the International Civil Aviation Organization (ICAO) Procedures for Air Navigation Services Aircraft Operations (PANS-OPS) Noise Abatement Departure Procedures (NADP) NADP 1 and NADP 2 profiles. Profile 1 is a climb with acceleration and flap retraction beginning at 3,000 feet (914 meters) AGL, which is the noise climb-out procedure for close-in noise monitors.
AERO - Fuel Conservation Strategies: Takeoff and Climb