BlueConcorde,
Look at my post #260, second diagram, taken directly from the BA Flying Manual.
There is a "first stage warning" (Mach/CG lights and gong) above Mach 1.6 and below Mach 0.45 for the aft CG limit.
It's only in the "corridor" that there is a "second stage warning" (flashing Mach/CG lights and stick shaker).
CJ