cam belt time

[Kenta8]

I have an 02 A8 4.2L. The Cam Belt was replaced at around 68K and it has now done 128kish. I am based in Kent but I do not mind traveling to get a good service. Essentially I was going to get the Cam belt replaced, have the car serviced and generally looked at. There are a few little issues I need to get sorted as well. Can anyone let me know what I should be paying for the cam belt replacement and if there is anything I might as well get done while they are in there? Recommendations for a garage would also be appreciated. Thank you for any help.