JA
Listening closely to the video of the original broadcast, I do think I can just about hear the "chatter" under big bens chimes, it's just been rendered quite indistinct by VHS noise and low bitrate digital compression.
Edit: Actually directly comparing the two side by side, the chimes actually start several seconds earlier on the Drama version than on the original broadcast version. On the Drama version they start as soon as they cut to Den, on the original broacast they don't start until he says "Make your new year's resolutions now". The point the drama version fades into the Big Ben footage is a few seconds later too- as you can see by the cars driving across the bottom of the screen, and the sound doesn't sync at the same point of the big ben footage either. So clearly a different edit made for repeats/international screeenings.
Edit: Actually directly comparing the two side by side, the chimes actually start several seconds earlier on the Drama version than on the original broadcast version. On the Drama version they start as soon as they cut to Den, on the original broacast they don't start until he says "Make your new year's resolutions now". The point the drama version fades into the Big Ben footage is a few seconds later too- as you can see by the cars driving across the bottom of the screen, and the sound doesn't sync at the same point of the big ben footage either. So clearly a different edit made for repeats/international screeenings.