This is what Choco said about him on his Monday segment with Francis Leach on SEN on 26th June which I linked in my op.
"He is an expert at the actual technique, but what he adds to it, which does intimidate some coaches and some clubs, is that he's a little different and that difference is the art of his coaching ability."
He has strong opinions, some coaches can't handle that, and basically if you get Ben Perkins in to help you, the head coach and skills development coach basically has to admit to themselves, they have stuffed up and haven't done a good enough job. People like to protect their little empires and don't or can't admit their errors
Interesting, so it sounds like given Ken's stubbornness as long as he is coaching Perkins probably won't be welcome to come in and prove him wrong.