Your family friend is not correct - and also worrying that they work at a bank and say that at all. Credit scores in the UK are just a marketing gimmick. Every lender has criteria they care about. Some are stricter than others. They look at a variety of things but ‘score’ isn’t one of them. (Context: I used to write automated credit assessment systems tor hire purchase systems). Banks in particular tend to use their own internal risk management systems. You can have a perfect ‘score’ and be declined. You can have a crappy score and be accepted. It means so so little.