Hi, CHUFF
My last post wasn't intended to be anything specfic, Just a couple of examples for you.
Hears a 22.5 cir use a 1/4 inch cutter the depth is set to Z-0.6, You may want to change the F10 speed's (cut) to a higher speed.
Jog to the center of your cir, Zero axises to just above work surface, Ctr. hole will be cut first.
This is hand written G-code, Should do what you wanted.
Hears a LazyCam, G-code file also.
Learning, Mach, Cad, Cam and G-code, Takes Some Time.
Hope this Helps, Chip