Carerra Automatic Service

[Paul S4]

A pal has aquired a blue Carerra chrono automatic, and would like to get a replacement bezel for it. Apparently he would need to send it to TAG in order to do this, but is there any way that he can get this work done via an independent specialist. Also, regarding servicing, how often do these watches need a service, since he is not entirely sure on the age of his watch. Presumably the serial number would help, but the back would need to come off ?
Thanks in advance for any advice.