Well, the brakes have been checked by the VW garage and are, "100%."
What they think happened, is that the brakes had cooled and been completely covered in water. This is entirely possible. On my way home from work I tend to keep my distance from the car in front and use engine braking only. A habit developed when riding my old V-twin motorbike. It had really good engine braking.
So basically I need to modify my driving style
In the rain, should I -
A - tailgate the car infront and be constantly dabing the brakes, even thought I have no opportunity/intention of over taking, thus having every driver behind me thinking I am a complete tosser in a car with flash led brake lights?
B - Perform an emergency stop every once in a while to clean the water off my brakes and waken up the drivers in the cars behind me.
C - Allow even more room approaching turns and junctions and get down the gym to work on my leg muscles.
D - Extend the brake pedal over to where the clutch pedal should be, so I can use both feet to brake.
Seriously though - on my way to the garage I had to drive around a 4 car pile up
2 cars looked like write-offs. Though everyone seemed ok.
So in the rain, keep your distance, dab your brakes rather than using engine braking and concentrate.
