What happened to your D3/D4 today?
	
	
		Following this video I have just repaired it successfully! Amazing!!
I could not bear the continuously flashing PB light. 
The right tools certainly make the job possible but once I had it unjammed and turning first using a long crow bar I could hammer from below the exhaust I could then literally spin it using a small screwdriver to flick it down. It would rotate a full turn at least each flick. 
Once fully retracted it just clicks back together to the other side. I then removed the wheels and cleaned and adjusted the park brake shoes per BBB.
Then I did what the dash display instructed to lift the PB lever and miracle of miracles it did a little dance and then applied the PB and all the flashing and errors cleared. 
About 2.5 hours due to how easy it was to spin it and with the park brake adjusted and cover re-siliconed and back on. 
I’m tempted to think that once it is freely turning lifting the PB lever as per the dash instruction would do the job of reconnecting it for you. 
Definitely must have been a few of these units chucked in the bin when all they needed was unjamming manually.
I REPAIR EPB MODULE on a Land Rover Discovery 3 / LR3 / RRS for 0$ - YouTube