The flaw with that article, it being the Beeb showing their bias, is that it mainly applies to the English Home Counties.
So it is a southern English habit, not a British one. The other parts of England are more direct, and will use more obvious phrasing. Similarly the other parts of Britain will be more direct.
Indeed. I've lived in the UK my entire life, and I've only ever heard "sorry" used to mean "excuse me, can I get past please?" in and around London. It still sounds weird to me. Where I come from (further from London), you'd just say "excuse me".
Glaswegian here, I would use sorry as an "can I get past" also.
Not quite. If you had to get off a packed bus with a large rucksack I'd certainly be saying sorry and I'm from Yorkshire.