ISTR there is a sort of wildcard entry which can be used as the last part of a postcode to refer to an area.
It can usually be used when a web page needs a full postcode.
For example, if I had a post code of BS49 4ER then I could use the wildcard to refer to only BS49 by entering something like BS49 ZZZ
Does anyone know what that "ZZZ" should be?