I just updated my address. It included the old county that my house was in 1965, as it’s now in London. I don’t use the county in my address (it’s been 61 years) so I’m worried the address won’t match.
What did Monzo say when you spoke to them?
I would check what Royal Mail has your address as. A lot of companies simply use their lookup for address information.
The robot said I should post it here as feedback
Royal Mail does not include the ex county, have a screenshot I can send Monzo
If the street name and postcode are correct then I wouldn’t worry. You can jump through some hoops to get it fixed outside of Monzo if you’re really bothered.