I just had the bluetooth kit installed in our TDV6SE by our local LR dealer, and it works great with our Nokia 6680's.
By the way, the passcode was 0000, even though this is a new kit. Will get the part number if you are interested. Apparently they had to install 2 modules, not just one. Price was a big discussion. They wanted to charge $1000+, but after a lot of armwrestling, I am going to pay $500 (we are in South Africa, and the impression I get is that we pay a bit more for parts than other markets). What have you been paying?
My humble opinion is that most of the time the handset is the problem when it comes to BT connections. I had a Motorola BT kit in my Disco2, which never worked properly with my wife's Nokia 6680, but always worked fine with my 6600 and 6680! All the settings were identical, but her phone frequently disconnected from the Disco.
Make sure you have the vehicle paired correctly, and that it is enabled to make connections without authorisation being required. (apologies if this has been covered already)
In my BMW I have an aftermarket OEM kit that I bought from TVonNav, and all the handsets I have tried work just perfectly on this kit.
Interesting that the BMW and LR kits use the same voice commands, and work almost identically, although I have a slightly german-sounding female voice in the BMW as opposed to the slightly english voice in the LR. LOL