There is a special tool, listed in the back of the Land Rover green bible that can be purchased, Sykes Pickavant(sp?) that would set you back about 130 notes
You can see this below along with the mock-up of my version. If you cannot read the part number then may I suggest you go to Specsavers
The other method is by grinder or oxy-acetylene torch; a replacement drop arm is a mere £ 5.
Lastly it is said that if the nut holding the drop arm is partly undone and the vehicle driven, the drop arm will loosen itself. My reaction to that is one, it is dangerous and two, you are forgetting sod's law which paraphrased simply is: anything you want to undo will not but those items you don't want to undo will.
When I needed to overhaul the steering column in my S3 lwt, I decided I wanted to keep my original drop arm namely as this would be superior to aftermarket copies.
I obtained a thick chunk of steel (20 or 25 mm thick - I should have measured it before posting!) and using a pillar drill made many holes to create the C shape. One more hole, tapped for a M12 bolt with a pointed end and there you have it. The drilling took many hours due to endless start/drill/stop/add cutting oil cylcles but in the end was worth it.
.. I think 
The dimensions are shown below. Note that the dimensions are tailored to my particular vechicle made to a hardboard template - so it may not be universal i.e. it may not fit yours.
and the finished puller, painted in black. You can see remnants of the holes drilled at the back and sides of the central gap - there was no point in tidying since it is the "jaws" at the opening that only need to be square.
Once put on the drop arm, a couple turns on the screw took the arm off - so easily in fact that I had thought I had stripped the bolt!
