I'm sorry Aviophage, I fail to see how BOAC has backed you up.
I think most who have posted so far would agree wholeheartedly with his statements.
Using speedbrakes with more than Flaps 5 (737)/Flap 1 (A320) is discouraged due to buffet and increased stall speed and never use speedbrakes below 1000' - completely agree.
But an airline thats 'not fond' of speedbrake use below 10,000..I mean come on, that's the only region you should need to use it, above 10,000 make full use of speed to get back on to profile. Below 10,000 90% of airlines and airports have speed restrictions that make the use of speedbrakes necessary when the situation changes. I would love to fly into some the airports you seem to because they sound like a breeze with no weather, ATC, other aircraft!
Planning a good idle thrust descent - definitely. Being ready to revise that plan and make full use of all the tools Boeing and Airbus have provided you when the situation changes, even better.
If you're turning down very reasonable ATC requests in a busy environment where you're not the only guy out there just because you don't want to use speedbrake, I don't blame them if they send you to the back of the approach queue to burn another tonne of fuel and turn up 20 minutes late.