Anecdote : I live near a busy high street in London and went out for my daily lockdown exercise at around 6pm today.
About 10% of the "highly educated population", as you say, was wearing a mask. Even more worrying, if you looked through the windows of estate agencies and other such ""essential"" shops, it was exactly 0% indoors.
To people outside the UK reading this : supermarkets here have only made face coverings mandatory a couple of weeks ago ("unless you tell us you're exempt", of course) because the government finally asked them nicely to.
All these months, their CEOs have been emailing us bullshit newsletters about how "your safety is important to us in these unprecedented times", and to that effect they were politely asking customers to "keep your distance" and "wash your hands" and "follow local guidance about face coverings" (i.e. "none"). Meanwhile their employees were free to spend their whole shift unmasked and potentially filling the air with virus, getting their colleagues and customers sick : that was totally cool. And no mention of any effort regarding store ventilation or aerosol risk either.
There is no enforcement of lockdown whatsoever, except for the most egregious cases of partying. It all seems to be based on a gentlemen's agreement, except there seems to be very few gentlemen left indeed. It is all so hypocritical.
This situation is in stark contrast with what I hear from friends & family on the continent. Last time I was in Paris for instance, mask adherence was probably 80% in the street and 99% inside shops. And the French are not exactly known to be fond of rules.
So yeah, B.1.1.7 probably didn't help, the government has probably f**d up on everything except the vaccination programme, but the behaviour of the population alone is in my view, more than enough to explain the terrible UK death/cases figures.