It is common practice at busy, large airports to maintain a high-ish approach speed on final approach, typically 160 to 170kt - until at 4 nm from touchdown. The gear would normally be up and the flaps at one of the early to intermediate settings (sorry, I donīt know what settings the 777 has available but on the VC10 I flew in the RAF it would have been the first stage, called "take-off" by Vickers).
At 4nm, the gear would be lowered and the flaps extended to reduce to "normal" approach speeds (again, Iīm not familiar with the 777 but the VC10 would have been about 120-125kt).
There are a number of reasons for the high speed approach including: all aeroplanes flying similar speeds for easier ATC spacing and low drag configuration allowing lower power settings, lower fuel usage and less noise.
The downside is that the aeroplane is not placed into the landing configuration until late on the approach and as the drag increases (gear/flap extension) thrust has to be increased to compensate. Normally, everything should be settled by 500' above touchdown - unless, of course, the engines fail to spool up when requested - then it becomes "interesting"!
As for disengaging autopilot at 1000', that is certainly NOT the SOP. Minimum height for AP disengagement will depend upon the type of approach being flown, the approvals for the ground installations and runway, crew qualification, aeroplane avionics fit, crew qualifications etc. However, a category one approach can normally be flown on AP down to about 100' above the aerodrome in most autopilot equipped aeroplanes.
Hope that helps.
Regardless of how fast you are going in a VC-10 "less noise" should not be used in the same sentance.
