It is three characters long. This Website use performance cookies to: Provide statistics on how this Website is used including selections that you have made and goods and services that you have viewed, during your use of this Website See how effective our adverts are Enable us to track and improve this Website by analysing visitor behaviour and results. National S avings B ank the district number 58 also approximates the outline of the initials SB. Since the local government reorganisation of London in the s, parts of Greater London lie outside the London postal area. Each postcode is divided into two parts separated by a single space: the outward code and the inward code respectively. The outward code includes the postcode area and the postcode district , respectively. Trustpilot contacts users with an invitation to leave feedback on their experiences with Royal Mail. The second part begins with a single digit, which indicates the postcode sector , and ends with the postcode unit.