This is actually quite annoying. I have some Chase cards from when I lived in the US that now have UK billing addresses and therefore alphanumeric postal codes.

This is actually quite annoying. I have some Chase cards from when I lived in the US that now have UK billing addresses and therefore alphanumeric postal codes. It's not uncommon for these to be unusable online because the form expects me to have a US address/numeric zip code. I know I'm an edge case, but it's surprising how often sites over-validate form data and exclude all sorts of things like telephone country codes, non-US states, shorter zips etc.