You've blundered in not realising there were two Richie Barnetts at Hull, both of which you mention in your post.

(and yes, he played , generally alongside Colin Best).

He had everything for a top full back except pace.

Unlike you on Mumby, I'm not going to diss Kemble, who was a decent player, but really, there is no comparison, as a defensive FB Mumby (who played nearly 600 games, almost all of which I watched) (cf Kemble's 200) really was in a league of his own.

The problem with the selectors was not that they picked Mumby, but that they didn't want to play him at FB because they wanted to use him as a defensive plug in the centres. Crazy.

I have never watched a FB who could tackle, defend and cut off attacks like Sir Keith could and I doubt I ever will.

Best fullback in the Superleague? Either Radlinski or Brent Webb

Best fullback I've seen play in the UK? E.T.

I think it was more lack of acceleration than all out pace, where he made up for it was his reading of the game, he always seemed to know where the kick was coming from or the angle of the runner and was in position to snuff out any danger. On his kick returns for his five prime years he would always beat the first man and offload with technique rather than pace. You could probably count on one hand the no of dropped passes from high bombs in one season, very unlike todays full backs who struggle to judge the path of a high ball and quite often let it bounce or lack understanding with the winger.
He was also very brave or suicidal covering a low bouncing ball, think he had 2 or 3 broken jaws/eye sockets colliding with opposition legs, bradford bulls cup game was one of them.

I wasn't dissing Mumby, I was ridiculing your ridiculous notion that Mumby was the GOAT FB from a defensive POV.