In the end, I had Halfords fit a Sony BT3900 unit (which only cost £90). The bluetooth module is built in, plus, it charges my iPhone when needed. No steering wheel controls, but, the button is not that far away! The caller's name appears on the unit's display.
The mic is built in to the unit, and I am thinking of having an external mic fitted (they cost about £10 on EBAY). I use a phone in the car quite a lot, but, so far no-one has complained about audio from the in-built mic , though that might change if I travel at higher speeds. The external mic on my Parrot in a previous car was superb, so, it is why I am thinking of upgrading it.
Another advantage is that I can stream bluetooth audio from my iPad, which I find really useful indeed.