ABS related Brake failure after Full Lock

Hi,
Been searching the various ABS related posts on here, and yes my light is pretty much always on.
However, more worryingly, after employing full lock my brakes dont work.
Read somewhere about it being the system thinking ABS was locked.

I may have a dodgy CV as well as it grinds a little after lock, could this be related to the fault?

I know its going over old ground, but thought my specifics, may enable a more specific fault