Hi
It's not a hard job!
1) Most important thing to do, is to disconnect the car battery for at least 20mins before you start (allows for the residual charge with it the airbag to dissipate away) :!:
2) On the OEM wheel, you will find 2 cover panels, remove these.
3) Your then find 2 screw / bolts with 'star' heads (they have a name, but can't think of it now
)
4) The airbag should now lift off, discount from the electric wire from the SRS activation unit / horn
5) Get a 'mate' to hold the OEM wheel, using a long handled spanner (or torque wrench) undo the center hub bolt.
6) Now pull the wheel, you may find it rather hard but tug a few times will free it.
OEM wheel is now off!
Remember to make sure when installing the new wheel the front wheels line up, and make sure the torque on the hub bolt is correct (can't remember it's value though).
With any replacement Steering wheel remember your need a Boss Kit. Also, remember that your still need to have a horn button (requirement for the MOT anyway).
Hope that helps
Mike