Disclaimer - This guide is aimed at those with some mechanical experience but is easy enough to be followed by all. If you mess it up tho, don't shout at me.
Tools you will need.
Two Jacks (or one jack and axel stands)
Torque wrench
17mm socket
17mm spanner (preferably ratchet spanner but not essential)
8mm socket
Ratchet
Rivet gun
Drill + various drill bits
6mm allen key (or hex bit with extenders if you don't mind a bit of modding)
Flat Head screwdriver
Jack up the front of the car so that both wheels are off the floor. Secure the elevated car with axel stands and remove both wheels. Now remove the front under tray using an 8mm socket and a ratchet to take out all 10 bolts.
The anti-roll bar is attached to the chassis by two brackets and each end is bolted to the ARB drop links.
To disconnect the drop links from the ARB, it is simply a case of using a 17mm socket on the nut which is holding it together. Unfortunately because of the way drop links are made the internal joint will just spin around inside. To stop this push back the rubber boot on the link to reveal a joint that you can put a 17mm spanner on to stop it from rotating. Use this method to remove the nuts on each side.
Chassis brackets are held on by two bolts fastened from the wishbone side. These are in quite awkward positions and make it a bit of a nightmare to remove them. The top bolt is obscured by a part of the aluminium frame but this has a hole in it (about 8mm) to allow an allen key to be inserted. This makes things quite difficult as the bolt is not accessible with a hex bolt and ratchet. The allen key way allows you to turn the bolt about a quarter of a turn per go. Using this method it took me nearly 15 minutes for one bolt. I decided that this was too hard so I used a drill to widen the hole out to 10mm. This allows a hex bit with two extenders to be used. It took less than a minute to get the second top bolt out.
The lower bolts are obscured by the lower wishbones and cannot be removed without moving them. You could remove the wishbone completely but I found you can just take the bolt closest to the front of the car out and knock it up a little using a piece of wood and a mallet. With the wishbone out of the way an allen key or the hex bit with extenders and ratchet can be used to unscrew the lower bolts.
Although the ARB is disconnected there are two aluminium panels riveted to the chassis and crash box preventing the bar from being taken out.
Drill the three rivets out and use a flat head screw driver prise the panel off the crash box.
Here is the bracket removed from the car
With these out of the way, lower the ARB out and put the new one in. Make sure you use plenty of lubricant between the new bushes and bar.
Then basically reverse the removal procedure to put everything back together. The only thing I changed when putting everything back together is to replace the lower bolts with some stainless socket head M8 25mm ones I had left over from another project (As you can see in the second photo). This made it loads easier to refit and will mean the wishbones won't need to be moved in future if I need to take them out.
The new ARB has five holes for adjustment, the closer to the front of the car the drop link is the stiffer the bar. If hole number one is the closest to the front of the car, I compared it against the old bar which was equivalent to hole number four. I set it to hole number three to make it a bit stiffer than standard. If I need it stiffer I will move it at a later date.
Edited by SteveA, 10 April 2009 - 04:31 PM.
Something I've been thinking about doing, tho I had no idea those plates were there to prevent it being removed, is there definately no way you could remove it by sliding it out from one side 
Geary's instructions say that it's not necessary to replace the little bit of aluminium plate (certainly doesn't do anything structural) but I did as it was just a simple matter of 3 rivets per side and I don't intend taking the ARB off again as it's adjustable in-situ.
