Many UK sites will start by asking for a postcode, which then lets them offer a drop-down of usually less than a dozen properties to fill in the rest of the add

Many UK sites will start by asking for a postcode, which then lets them offer a drop-down of usually less than a dozen properties to fill in the rest of the address, guaranteed to be in standardised form. The databases aren't always as complete as the developers believe them to be though -- sensible operators will leave a way to override the lookup, others lose out on custom from people living in new estates.