That's not quite true - there's a 5 yearly Health Check which is offered to those over 40 with no other known health issues (in England, but Scotland/Wales/NI have similar schemes).

Local councils are responsible for arranging invitations for those not currently registered with GPs, so it ought to be more or less universal - though there are inevitably a few people who'll slip through the net.

It's pretty basic, but the evidence suggests it's been reasonably effective at dealing with the "he didn't see a doctor for 40 years and then just dropped dead from a heart attack" stereotype.

https://www.nhs.uk/tests-and-treatments/nhs-health-check/