When a member tries to register and presses 'Submit', an error message is reported, saying that the Postcode must be exactly a NaN character. The visitor is unable to register. I imagine that an NaN character is a 'Not a Number' but I have no idea how to solve this problem. UK postcodes (and that is where I am based) generally consist of a combination of 1 or 2 alpha characters, 1 or 2 numeric characters, a space followed by 1 numeric and 2 alpha characters. For example: BB12 7AD or S22 1QJ or N1 3AB.
Can anyone offer a solution please?