This is all pretty subjective... however...

The other local who went to Euro F3 at that time was Wal Donnelly. I would think that Walker and Donnelly would have been rated fairly similarly, very capable drivers though we saw more aggression from Donnelly in the Turner than Walker in the Brabham. But I was not aware of Walker before he got into the Brabham and we had little to compare.

Barry Collerson had been around for a long time by then, incredibly enough having raced the Lago Talbot (a 1948 Grand Prix car) for some of those years despite his diminutive size.

I'm afraid I think of Kurt Keller as a shifty car salesman more than I do as a driver!

Oh yeah, the other local driver to go into European F3 at the time was Jim Sullivan.