Agreed Hargrave looks highly suspect but so does Carruthers! Jesse Glover saw Bruce Lee very early on after he came to the States, he was not there when Jeet Kune Do came into existence nor did he see how far Bruce Lee developed.
Here is Joe Rogan UFC commentator on Self Defence :
He makes good points, especially that a lot of what is taught in Self Defence won't work on a skilled opponent! To think no chance you will meet a skilled opponent in Boxing, Wrestling, MMA....... in the street is naive. What Tommy Carruthers teaches absolutely would not work on someone skilled in MMA even just the unarmed stuff, his defences against knives absolutely would not work against a skilled Filipino Kali exponent armed with a knife. The stuff you see Carter Hargrave doing, any skilled opponent would run right through you.