Adding a country code filter

[michaelwood]

Capturing this discussion from @KDuerden for possible incremental improvements:

Using UK-wide geocode in our tools

There is now a not insignificant number of grants that using the UK-wide geocode in their beneficiary data - K02000001

Currently these show as Undetermined, in the same way that incorrect / unrecognised geocodes or no geodata would do. I'd like to propose that we do add this as a valid code, because strictly speaking these grants are not undetermined.

This would be treated like England, showing in the Country and Region filter when it is specifically declared - not like Region or Scotland/Wales/NI which appear either when specifically declared or when a lower level geodata has being included.

Country code filter

[ ...] Discuss the above proposal alongside the plan to add country code filter, to help make international grants more visible.

In my opinion, a UK-wide geocode in beneficiary location field is not equivalent to GB country code declared in beneficiary country code field.

The first is describing an area of impact of a grant
The second is describing the country which benefits from the grant
With a GB country code the actual area of benefit could be at any level from a single estate up to UK-wide. Therefore the UK-wide geocodes in beneficiary location should sit with the other area geocodes and not be integrated or treated as equivalent to GB.

[mariongalley]

Re: non-UK Countries, our initial proposal was to have one value of "Non-UK" in the Countries/Regions picker, but we've more recently discussed the possibility of having a separate country filter that lists specific countries - is that the intention with this ticket @michaelwood