The pub at Shepherd's Bush roundabout was The Duke of Clarence.

I wonder if The Leveller is thinking of the right Marquis?
Clanricarde Gardens is by Notting Hill Gate tube. It's a two-stop tube ride to Lancaster Gate then a hike up Sussex Gardens to Southwick Street on the eastern side of Paddington to reach where Clanfolk used to be. And didn't it also move to Camden Town for a bit to a pub at the top of Parkway that's also now demolished?