[Talk-GB] C roads again

[Philip Barnes]

We have discussed this subject a couple of times and have, I think,
concluded that displaying the ref (generally only known to local
government people) on roads that are unsigned is not helpful to the end
user. 
Some, but I suspect not all, of the thread starts are below.
https://lists.openstreetmap.org/pipermail/talk-gb/2011-May/011632.html
https://lists.openstreetmap.org/pipermail/talk-gb/2013-March/014555.html
https://lists.openstreetmap.org/pipermail/talk-gb/2013-April/014788.html 

Ignoring the source information for now, but I suspect it is very
similar to rights of way information in that it is probably derived from
OS maps.

The following overpass query highlights the issue, Norfolk standing out
as especially bad. This is just tertiary roads, there are issues with
unclassified too.
http://overpass-turbo.eu/s/4xS

I am going to use the horrible word, mechanical edit, but I feel it
needs sorting out.

I propose that nothing is removed, but the ref tag for tertiary and
unclassified is moved to official_ref. This will retain the data and
allow OSM to be used by those who can make use of this data.

I know we should not tag for the renderer, but I think its ok to give
the renderer a clue as to which are displayed on signs and which aren't.

Phil (trigpoint)