It is nothing to do with a flat battery, turning the key in the lock to unlock the column lock is purely mechanical on a Disco 2.
To unlock the column lock you do have to wiggle the wheel as well.
If that doesn't work then the problem is still mechanical.
The key turns in the lock due to it sliding the wafers in the lock until they are just inside or flush witht he surface of the lock barrel, when this happens the lock can turn.
BUT as the lock and the key wears the key can no longer move the wafers far enough so bits of them maybe even just one, still sticks out far enough to prevent the barrel turning.
You can fix this by taking the barrel out and filing down the leading edge of the wafer so that even though worn it'll still work. No need for a new lock and barrel and onl;y about as much work as changing the barrel, without the need for fecking around with keys.
There is a thread or two on here about how to do it as there are elsewhere on the web, I'll try and find one for you.
I have done this, which is why i know it is possible.
Short term try wiggling the key around while wiggling the wheel. once you get it to unlock the column then it should move to all the other positions. When you want to stop you can then turn it back to JUST before the unlock and extract the key position. All the electrics will be off but the key will still work next time you want to use it. I had to do this for a while, I just locked the door with another key and hung a washleather over the steering column to hide the fact the key was still in.
Not ideal but it meant the car could still be driven.
But best of all would be to find the second key if you have one.
Here is my thread on it.
https://www.landyzone.co.uk/land-rover/making-your-ignition-key-work-in-a-disco-2.359475/
