Support Geocoding of co-ops in Northern Ireland

[ColmDC]

Is your feature request related to a problem? Please describe.
No co-ops based in Northern Ireland appear on the Co-ops UK Map

Describe the solution you'd like
Co-ops UK data processing uses a different method of geocoding from all later projects. It used an ordnance survey system that returns long lat by postcode, which does not support postcodes from Northern Ireland. It needs to support them.

Change the system for Co-ops UK data to use the coder we use for other projects.

Describe alternatives you've considered
There may be another OS solution which now includes NI postcodes but a v quick look did not find any.

Additional context

[wu-lee]

This is now deployed. You should see pins in both Northern Ireland and Jersey. I needed to work around this first however. #21 (comment)