I'm not quite sure why 42 Osborne Road was filtered out by one of the SQL stages. I'll take a look at that next time I'm in all day and can run each step one at a time and see why that happened.

There will be other gaps because the script which processes the OSM XML file halts at 100 features or 10 postcodes, whichever comes first.

The main aim of this is to get as many missing postcodes into OSM as I can, so I won't worry too much about gaps now.