Following a comment on my original post listed above, it appears the structure of the CodePoint data file has changed. This means that the importer will fail when attempting to import the latest data files supplied by Ordnance Survey as the columns in the files have changed.
I’ve pushed an update to the project on GitHub to address this - it now takes a sensible approach so the index positions are no longer hard coded. Instead, the CodePoint importer now takes an extra argument - the path to the CSV file that contains the column header listing as supplied in the supporting docs in the download. The column indices we are interested in (for Easting, Northing and PostCode) are worked out from this. Obviously makes it a bit more future proof, so if the structure changes again in the future, it should pick up on that automatically.
This is an update to the CodePoint import only at the moment as I haven’t had time to check the Scale Gazetteer import as yet. See the project/readme on GitHub for more info.