Mine was a December 2010 car so I don't see how the dealers can't fit Bluetooth or cruise muppets go to a different dealer
Dealers won't fit Bluetooth (other than the stick on Touch thing) as it's not an approved accessory and uses a non genuine wiring harness. Each car comes from the factory with a bespoke wiring harness depending on what equipment it has fitted. The additional wiring for Bluetooth is not available separately from VW parts. They just don't make it.
The kits that many of us have fitted use an aftermarket loom that plugs between the radio and the Bluetooth module, which VW won't guarantee.
Do you gave a link for this guide mate?