Having been in lockdown for the last week, I have to say, you get used to it. My BF, who is naturally more inclined to want to go out, hasn't left the apartment in days. I find excuses to go out - making all kinds of doctor's appointments, doing small food shops, exercise, taking the bins out at the wrong time so I have to put them on the street, etc. But I spend almost all day inside now.
The UK government will progressively issue stricter rules, as they have done in France. I saw no police checks for the first few days. Today I saw 7 in my time outside. They have clarified that exercise can only take place within 1km of your stated residence, and you must timestamp your "attestation" explaining why you are going outside, to prevent you from using the same "food shopping" one all day.
All in all, I'm at peace with another 40 days of this. I figure, let's do it properly, and then go back to normal, rather than do it half-heartedly and drag this out for months.