yeah, pretty much all UK roads have a name and a number.
And these will typically be implemented as numerous individual ways in the database (potentially hundreds, for a long numbered route - but even a short named road can have numerous ways).
But given that pretty the entire UK road network in OSM is currently done using just ‘name=’ and ‘ref=’ tags for these on individual ways, and it works fine, I’m not sure what problem we’re trying to solve here? 
To further confuse you, sometimes scenic tourist driving routes are signposted with brown tourist signs, explicitly named on the sign as a ‘route’. And then there is a whole concept of Making sure you're not a bot! ‘Primary_Destinations’ which can be expressed as destination route relations.