Thanks ... Yes I do get a message on the handset when a call is made using the BMW NAV monitor, however it always says "transfering to phone". My T637 would say "transfering to BMWxxxxxxxx"

I went through the various Bluetooth options, and under settings > connectivity > bluetooth > handsfree > incoming call you can direct sound to always use the handsfree BMW system. So incoming calls work great. Its just the outgoing calls.

This could be a compatibility problem with this specific TCU ... although its one of the later TCUs and its ashame if it doesn't work and this is a really nice handset !!