Im doing mine tomorrow, recon one all the way, 12 month warranty.
Look on here for a thread with alternator, some guy emailed me a link on the williamsclio.co.uk forum which has pics, loads of them on a step by step guide to do it. I reckon 2-3 hrs, 2 if everything goes well, to get it done, off and new one one.
Just a case of headlight out, loosening the bracket bolts and your away
Cheers
Leigh