This is not a lockdown. Stuff is closed, yeah, but apart from that people are doing whatever the fuck they like.
There's a few things working against the lockdown this time.
Some people have had enough of lockdowns and can't be arsed any more.
Some people don't take Covid as seriously any more. When it first hit no-one knew quite what would happen. Would people be coughing themselves to death and collapsing in front of you in the street? Would there be mass graves? Covid has been more subtle than that. Individual risk is low - lots of people know someone who's had it and just been a bit ill - it's just that a death here and a death there quickly adds up, but there isn't the carnage that might've been envisaged.
Then there's the new rules. They start off with "Stay at home, except for specific purposes", but then the specific purposes include: going to work, going to school, taking the kids to school, going to college, going to university, going to shops that are open, going out for exercise, taking the kids to a playground. Between those, there's plenty of reasons not to stay home.
The rules allow shops to open for click and collect, so loads of shops that were closed last time are still open. Cafes can stay open. Shops that sell a wide definition of essential goods can stay open. And if they are open people can to go to them.
No arguments about what counts as exercise this time, or how long you should be out for, just "You should minimise time spent outside your home", so basically 'do what you want'.
You're only supposed to meet one person from another household, but then you go to work or a shop or do the school run and that's impossible. The kids are in "bubbles" of over 100 other kids. It doesn't encourage people to stick to just one person for their social lives.
When it was announced Johnson gave one of his rambling speeches that left people vague about what the rules are. Follow up interviews the next day showed a range of ministers didn't know the details of the rules. It didn't inspire confidence that the people making the rules didn't know what they are.
Then on the day the lockdown started all the news was talking about was the US election and that's been the main topic of conversation since. The main mention of the lockdown was the much publicised (especially on the BBC) complaints about the figures used to justify the lockdown - the graph said 1500 deaths per day, but should've said 1000, as if a thousand people dying every day is just fine and dandy.
It's hardly surprising that it's not been much of a lockdown so far.