LHR??? standard speeds into the TMA .77/270 now.
It would seem that many people are doing 250kts (ish) so even at busy airports it should work quite well.
Going into AGP it doesn't really matter what speed anybody is doing as madrid ATC manage to hand over all the traffic to Seville completely unseparated anyway!!
I know following slow aircraft is a little frustrating but it actually makes little difference to your arrival time but quite a big difference to the savings to the Company.
factanonverba, I didn't understand a word of what you were trying to say, but I guess that the gist was that you don't necessarily make a fuel saving by descending at a slower speed? I would have to take issue with that.