If it helps, for people training for LHR, it is almost physically beaten (well, almost *grin*) into you to issue range from touchdown as soon as practicable to the descent from FL's to altitude when being positioned downwind. I have always worked on allowing descent that will roughly equate with a continuous 3 degree "glide-path" ROD, 18 miles - 6000 ft (keeps the math simple.....I like simple). Sometime this isn't possible, especially if you require an increased ROD for separation, expecially if we are landing on both runways and you are trying to get the first guy down so you can run the following for the other runway over the top of him and not trying to keep him too high above the glide (that make sense?).
It does make me smile though when a certain flight (who shall remain nameless) is told no speed (being the only jet in the sky), given a range from touchdown, and then comes down like a brick and levels for ages. Good fun trying to apply night noise descent restrictions.
