Basic requests like the one below - where the postcode is missing - return an internal server error (oddly formatted as HTML, too):
.../~$ curl --data "address=22 greenway berkhamsted" https://sorting-office.openaddressesuk.org/address
<h1>Internal Server Error</h1>.../~$
An incomplete address should be recognised as such, possibly with a null postcode result. What do you reckon?