LUV744
I am not sure that you wanted the answer to be specifically about 747-400s landing at LHR. They do land other places in the world <bg>.
I used to fly for UAL and now for China Airlines on the 744.
I always loved EGLL and do not get there any more. Maybe someday again if LHR opens up and anybody can fly there. WHo knows?
Most pilots would fly the 744 faster (and more fuel efficiently) if it weren't for ATC and lots of other airplanes. I am laughing when I say that (no rock throwing),but LHR is a very busy place and the controllers do a good job. But people who fly to LHR know that most of the time you get a customary one turn in the holding pattern! LHR has speed restrictions. I would say about half of the world's airports have speed restrictions written on the JEPP chart. The rest will tell you what they want you to do.
Some carriers are more specific than others on how they want their airplanes flown with speed and flaps. A 747 with less than an hour's fuel is a great glider and is hard to go down and slow down.
727s could be flown to the outer marker at 250 kts clean and still land,but the newer generation airplanes like the 777 and 747 can not be. So the numbers you had were quite reasonable,but slower than most people would fly if other airplanes were not an issue.