I tweeted about this a while ago, some ‘interesting’ ideas for test addresses (including postcodes/zip codes) in the replies:
See also the replies to:
Anyway, this led to me writing this blog post, which discusses what we could/should consider when using test data such as postcodes:
http://rightsaidjames.com/2017/05/improving-test-data-management/
My personal favourite is the postcode for Downing Street (SW1A 2AA), which I suppose is similar to Buckingham Palace in that it’s a famous address but also not particularly atypical of a normal UK address in terms of how it looks written out.
Another category of post codes I didn’t see mentioned above are those for armed forces members living abroad - you can send post to them via the British Forces Post Office. The Wikipedia article gives the example of ‘BFPO 61’ which corresponds to Milan, Italy. if you specified the individual + company + regiment along with this then it would eventually be sent to that person (or a safe location nearby) wherever they happened to be stationed. The article goes on to say that UK-style postcodes starting with ‘BF1’ were introduced in 2012 to accomodate online systems that don’t support the BFPO format - ‘BF1 2AY’ would be the equivalent of ‘BFPO 61’ - the address is then translated back into BFPO format before it is sent abroad.