Update to this with a weird issue. When the engine is on the sensors seem to go mad, the front ones mainly, always seem to cut in on the rears for some reason. Yet with the just the ignition on and the gearbox in R they work perfectly? You can go around to each sensor with your hand and it detects the space perfectly, start the car and then they go mad again!

So any ideas? PDC module at fault and needing replacement? Overvoltage maybe? I'm getting no faults on Carly for BMW.