I think Brits are generally fairly good at following rules, far more so than Southern Europeans or the French (perhaps less so than Germany, Scandinavia etc), based on personal experience of living in various EU countries. However, in Britain lots of rules have at various points been framed as advice, whereas in (culturally less rule-following countries) European countries rules were very strictly implemented through police checks, forms, fines etc.
I agree with the PP’s comments about preventative healthcare - this is also emphasised more in some European countries, where frequent check-ups, blood tests etc are normal rather than the British way of only seeking help once a problem is bad. That contributes to better health overall, and to a culture of seeking medical help quickly when ill, both of which could be factors.