There's been a few people who's had to have their DS towed but have no idea how to get the DS into full time neutral without turning on the engine.
I'd like to suggest a few things.
#1 call LR roadside assistance and they'll send out a qualified tow company that should know how to activate the override. Just make sure of that when you cal roadside assist.
#2 call your dealership service dept and ask.
#3 you can try the following procedure. It supposedly works on Evoques so it should work on DS.
Ignition on : then press brake pedal and hold, and at the same time press and hold the + paddle for manual gear shift - for more than 10 seconds. Then the selector raises. Select neutral.
I have not tried it yet. I just found out about it.
I'd probably confirm it with the dealership first before I try it.
But if anyone tries it without checking with dealership, AT YOUR OWN RISK. Please report back.
However I have no idea what to do if you have a dead battery. I believe RR has a manual override switch/lever hidden under the cup holder. I believe it works mechanically so no power needed.