Well, Londonmet. Since you're always flying into the mains I wouldn't expect you to understand, anyway. Landing config at 20 NM is of course never required, nor expected in airspace around the main airports. However, trying to ridicule a perfectly feasible option, speaks for itself. Try that attitude in Spain/Poland/Italy. Sometimes, you just have to get it sorted. Period. Or start a dispute with ATC, and they won't understand. Capish??!
I hope everyone agrees that in the mentioned scenario (with 250 below FL100), speedbrake will not get you down in time. You'll then end up around 3-4000' high above threshold.
(Speedbrake above 300 is not good, no limitation though. Extending gear/flaps a little early is a better option. Just check FCTM + Bill Bulfers Cockpit Companion + Pat Boones Mgr)