(For further details see Appendix G).

Using postcodes to assist in geographically referencing an Addressable Object:

• Postcodes should not be used to help indicate a geographic identifier of an Addressable Object. The purpose of a postcode is for the Royal Mail to identify a delivery point for an Addressable Object, not to indicate a geographical representation of the position of an Addressable Object in the real world.  For example, a church can have an address with a pseudo postcode allocated but it is unlikely that the church building itself has a letterbox, rather the post is likely to be delivered to, and therefore be allocated the postcode of, the associated presbytery or vicarage which possibly is not in the same postcode unit as the church itself.
• Some LLPGs include Records which do not formally have a postcode allocated to them at all (they are non-postal, or not known to Royal Mail), but which are allocated a pseudo one in the LLPG and therefore in GeoHub.  An example is lock-up garages which may have the nearest house’s postcode allocated to them.
• This scenario is dealt with in the current guidance by the addition of POSTAL_ADDRESS = “A” - Assumed or “P” - Pseudo postcode see Section 7.3.5.12. If a Record is flagged in this way, then this is an indication that the postcode quoted is not allocated by Royal Mail to the Addressable Object.
• Postcodes are susceptible to typographical errors. Just one digit wrong can make a BLPU appear to be in an incorrect postcode area. An error in a Street Name, on the other hand, would usually result in a match failure, so the fault would be spotted.
• In areas of redevelopment, new buildings are often allocated a different postcode from that of their predecessor.  Use of the former postcode leads to properties that cannot be located when geocoding data with an updated postcode look-up table.  This is an example of bad practice which must be avoided, but, if such practice was used in the past, then each Authority Address Custodian needs to be aware of potential inaccuracies in their data and ensure these Records are corrected.

The following provides some ways in which an Authority Address Custodian can establish the correct RPC value coordinates for a BLPU:

• By searching the internet to find a photograph.  This can be useful for locating the building on aerial photography. However, be aware that if the website visited is not the official website of the organisation, the information might not be accurate.
• By speaking to the company currently occupying the property.  Telephone numbers can often be found on a website or in a directory.
• By asking Tax and Revenues inspectors who often have extremely good working knowledge of their clients and areas.
• By asking the Environmental Health or Licensing functions within the SNN Authority if the property requires SNN Authority licensing under the Licensing Act or Food and HELA inspections under the Act.
• By using their own local knowledge.  This is one of the best sources of commercial address change intelligence.  The knowledge of an Authority Address Custodian familiar with their geographical area should not be underestimated.
• By liaising with the local VOA office who, possibly, can supply site plans of commercial properties. This can often enable an Authority Address Custodian to associate a BLPU Record with specific building or land parcel.
• By establishing a good relationship with the managers of town centres, shopping centres and chambers of commerce.  Possibly, they can provide information on when and where different shops are opening and premise names have changed.
• By liaising with the officer responsible for carrying out duties relating to the Factories Act 1961.  Under section 137 of this act, factories must keep the SNN Authority up-to-date with various details including the name of the occupier or the title of the firm, the Postal Address of the factory, and the nature of the work.
• By liaising with the Estates or Facilities function if the SNN Authority owns or leases commercial units.
• By liaising with the officer responsible for carrying out duties under the Offices Shops and Railways Premises Act 1963.

• Possibly, the Council Tax inspectors in a SNN Authority can help.
• If a SNN Authority uses its own officers to deliver leaflets, letters, poll cards etc., those officers can often provide useful information, for example, details of flats with access from the rear of a building.
• The SNN Authority’s refuse collection or Streetscene service operatives can be familiar with the geography of the local area.
• Building Control and Development Control staff often have extensive knowledge of where properties are, and know local names for places.