Max rate and Min Radius are one and the same. Check your books.
(my bold) Alright, try the Royal Air Force's FTP/002/2 'Aerodynamics and Aircraft Performance':
"The speed for maximum rate of turn is that which corresponds, on the minimum radius of turn graph, to the point where a tangent from the origin just touches the minimum radius curve. Fig 3 shows that, at any given altitude, this speed is higher than the speed for minimum radius."
Lads, it is ever so elementary .... Best of Luck!! And keep trying!
Patronizing airs aren't always underpinned by knowledge!
Edited to correct for finger trouble: somewhat obviously, minimum radius of turn graph was mis-written as minimum rate of turn graph. Apparently, that makes me "a clown". Ah well, c'est la vie!