In the UK we most likely do not use county names as many of popular counties have a bit long and annoying to type names, like "Cambridgeshire" or "Greater Manchester". We mainly rely on postal code, city and street address to get the proper address details. My proposal is to just change this particular field property to be able to untick it as required. I know that there is an option "Require address" which can be unticked, but this makes the whole address block (street address, postal code, city) non-required - I would rather avoid passing the form with an empty street address or postal code.