AD's must have a Rolex approved watchmaker on the premises. (or within the group)
This was made part of the AD's contracts a few years back as an effort to reduce servicing turn around times in the uk. At that time it was taking 8 weeks to get your watch back.
The idea was that the AD's could do mainly datejust work, leaving bexley free to concentrate on the other models and turn them around in 6 weeks or less.
I have seen some watches serviced by AD's and I was not impressed.
The case polishing was embarrassing.
I have heard of watches that have been back to Rolex "5 times" and they still don't work. When the caseback was removed there was not a single service mark from an RSC.
Today UK RSC turn around is up to 10 weeks.
Well worth the wait...