Thanks Paul.
I have the iPhone (version 1 imported from US, no 3G). Yes you can only play audio from it either out the headphone socket or through the dock connector. The dock connection to line out provides the best sound. No bluetooth audio streaming.
The iPhone plays audio via any iPod car kit / FM transmitter etc. (I have harman kardon drive + play ready to install, currently just running a cable from the headphone socket which IMO is lousy).
And I just need something to cover the calls (iPhone can only do hands free via bluetooth or the provided ear phone set), so the bury kit using bluetooth is spot on as the iPhone can't do a wired dock connection anyway
Thanks for the info, I'll have to see how hard the install is. Should be easy if its bluetooth.