Doing the same for "National Cycle Network Route 5" we get to https://www.openstreetmap.org/relation/19284284 (you'll notice when you click something the URL bar changes).  You can also see on that "browse" page that it says "Part of 1 relation Relation 5 (19284290) (as main)".
That's the "superroute" (a "relation of relations", created because individual relation size is limited).
That has 10 members:
"    Relation 5 (359098) as main
    Relation 5 (19284288) as main
    Relation 5 (19284285) as main
    Relation National Cycle Network Route 5 (19284284) as main
    Relation 5 (19284287) as alternative
    Relation 5 (19284286) as alternative
    Relation 9466687 as connection
    Relation 9466685 as connection
    Relation 9466688 as connection
    Relation 9466686 as connection"

So that's 4 main parts, two "alternatives" and 4 connections.  You can click on each of those on that page to see what they are.