After reading how to do it in my Haynes manual I decided not to do it myself. I have done many before but they were not twin cam or air conditioned and did not have engine mounts in the way. If you do decide to do it you will need a camshaft locking tool off ebay.
Thanks for the reply BillyNoBand.
Im not fussed about the engine mounting i did a fan belt on a vectra last year!
Ill get that locking tool ready thanks.
Ill see if anyone has a walkthrough before i spend 20 on a manual.