UK Give Way signs

I’m new to OSM, and I’m confused about Give Way signs in the UK.

According to the government Traffic signs manual, Chapter 3, (3.1.1), the indication to give way may be given as (paraphrasing):

a) a double dashed line painted on the road,
b) optionally with an approach triangle painted on the road,
c) optionally with an upright sign by the side of the road (a red triangle saying GIVE WAY, possibly up to 12m away from the line).

So the double dashed line is the primary indication and the others are optional.

Additionally, (3.1.6) “The Give Way marking is not normally used at private accesses, or on minor residential roads where traffic speeds and flows are low and visibility is good.” That is, in some places there’s a legal requirement to give way but:

d) no sign at all.

I’ve read about Tag:highway=give_way and Key:road_marking but I don’t see how to make them do what’s needed or what the best compromise would be.

In particular, for a) and b) how should we indicate that there’s no upright sign?

For c), where should the traffic sign be shown—where the upright sign is, or at the junction?

And for d) am I right in thinking that if there’s no sign of any kind on the ground there should be nothing in the map?

A,B. traffic_sign=no?
C. At the sign.
D. This is the default legislation. Should not be added.

I wonder if question this about the rendering of the data in OSM or about what data should be put into OSM (the database) to allow proper rendering of a map?