I am having the same issue. We're based in Lancashire in the UK, and we deliver nationally. Every day I need to correct a number of addresses manually using Royal Mail's address checker, as well as contacting customers for their house number. There absolutely needs to be a way to disable this 'feature'. I've placed test orders and even my own address postcode 'suggestion' is incorrect. It's not obvious that you can override the suggested address with your own, so the enter experience is frustrating for our users.