Update - I recently got my vehicle back from the local dealership. They replaced a faulty wheel speed sensor.
On 3 occasions to date I have taken the vehicle and thoroughly rinsed down the wheels and brakes and left the vehicle parked overnight.
So far I have not experienced the severe loss of braking when I first move the vehicle.
Hopefully this is the fix. As a point of interest the vehicle was acting up for quite a while (2 months) before I had the ABS/Serv 4WD warning light activate on the instrument panel.
I will keep you all posted if I have any further issues with the brakes.