Like Scott, I wouldn't habitually do what they were doing but apart from the hard shoulder undertake I thought they were pretty smooth & tidy riders.

At several points I did feel the cars they caught up & followed for a time could have moved over out of the way and let them past - would have reduced the need for an undertake. But then a lot of car drivers won't do that out of awkwardness, idiocy or simply don't look in the rear view & see what is there!

BB