What relevance does your credit score have to day-to-day life in the UK?
As far as I can tell mortgages are dependent on you having OK credit, not good credit. You don't seem to get better rates dependent on your credit score.
Credit card rates are irrelevant, you shouldn't be carrying a balance.
Some people have a Pavlovian response to anything with credit score. The propaganda has worked. In the US, we have countless TV commercials about "Check your credit score!"
As far as I can tell mortgages are dependent on you having OK credit, not good credit. You don't seem to get better rates dependent on your credit score.
Credit card rates are irrelevant, you shouldn't be carrying a balance.
What else do you really need a credit score for?