I figured I should update this thread as the problem has been solved.
It turns out the brand new rotors I installed both had a manufacturer's defect. When mounted to the hub the face of the rotor was not perfectly parallel with the face of the hub. This caused one of the brake pads to be pushed too far away from the rotor as the wheel turned. Hence why as soon as the car rolled I would loose brake pressure... seems all so simple now
FWIW, these bad rotors were purchased locally. The replacement rotors bought from our host are working perfectly.
d.