If your Bentley uses the 10 CD system, you can buy the BMW 11 CD set, numbered 65-90-2-365-696 that will work. (although Your Mileage May Vary )
I put the Canada CD into my CGT today, and it worked fine creating a navigation to a town that wasn't even on my Bentley disk (FWIW, Nanaimo, BC).
The disks are labelled as the 2015 versions, and the documentation indicates that this will be the "Final Version" of the CD product, so if you are interested you may want to get them sooner than later.
I paid $200 CDN from a local BMW dealer, and posts in the Phaeton forum say you can find them from BMW sources for $150USD.