There are many missing postal codes and cities in the Northern Ireland data. I have attached a file with the corrected and added places and codes. The added items can be detected by a lack of longitude/latitude information. These are all the postal codes beginning with BT.
Hopefully these can be geocoded and added to the database.
I have a doubt with the place names in the list. According to this wikipedia page the additional placenames are not listed in the column 'post town', but rather in the column 'coverage':
http://en.wikipedia.org/wiki/BT_postcode_area
Couldn't it be misleading if we were to add them in the same way as the other entries?
Northern Ireland does not yet have the same open data strategy as England/Scottland/Wales and the full postal codes are not yet available for open usage.