I got a reply to say:
“We rely on a third-party postcode lookup service, and currently, this postcode (PE12 6JP) is not returning any results through that service.
The postcode you see in the database was manually entered, which is why it exists in our records but cannot be retrieved via the postcode search functionality.
We understand this can be confusing, and we will raise this with the third-party provider to investigate further.”
I’ve told them that I have yet to get their system to accept any postcode and sent them a list of the ones I have tried (all of which are valid postcodes for fuel stations in their database).