To remove steering wheel..
Disconnect battery from the car and leave for about 1-2 hours for the airbags to fully discharge.. believe me you dont want an airbag going off when you have your head right next to it trying to remove it.. it could kill you !
Once you have left it with the battery disconnected feel round the back of the steering wheel and you will find 2 metal clips holding the airbag unit on.. you can use a flat blade screwdriver to prise them out afterwhich the airbag unit will pop out.
After that you need a bit torx driver (you can get an appropriate one at most halfords, i bought a torx one that attached to my normal ratchet) and undo the bolt almost completly... the trick here is to leave the bolt on a couple turns so that when you pull the steering wheel off you dont hit yourself in the face with it
once the wheel is loose, undo the bolt complely and remove steering wheel !
Job done !