On a sunny day I Got the message "Phone not fitted" - the so popular bluetooth message. My BT was working everyday, so I was quite surprised as this is a non expected fault... I couldn't figure out what happened prior the message irregular. I searched the so many threads on the subject, checked the rear F29 fuse (in the car book referenced), removed the middle hand rest just to see everything is fixed tightly in place (I just removed the center section, not the whole unit as it is a more complex job for the short time I had... Afterward I pushed the phone+menu buttons for 5 seconds and enetere the 1971 code, marked v on the phone option and nothing. It return to not marked.
Eventually I looked at the DVD compartment at the rear, finding nothing. Just a DVD. It confused me as I read a lot on the other threads that a module is to be expected aside the DVD there. But I had nothing.
A day later I remember that when looking at the DVD area, I saw an unconnected plug hanging over the DVD. I removed the panel and find the fiber optic connector and the other part it should be connected. Joined the two and here we go... all is ok.
I have no idea why it popped out. Maybe someone (My kids are using the car) had his hand there... Whatever.
I find no reference for 2007 BT issues in the forum, so there is mine. Pics added..

 

Glad you fixed it. I just received the same message today. It coincided with no sound from the radio although the radio display worked fine. Do you know if your radio sound was functional when you had the "phone not fitted" message?
Thanks

 

Hey David.
I did have Radio sound. I got the "phone not fitted" message and nothing else.
For my case - it was a popped-out fiber optic connector on the left side DVD drawer on the trunk.
As far as I learned - sound from devices is routed by fiber optics to the back to the left drawer area and combined there. The exact layout depend on the year and type of the car, this is why I couldn't find anything like mine. But the idea was clear. Unfortunately I don't have enough knowledge on the audio systems - but it was discussed a lot on the forum. I am sure you will find your answers.
However - before anything else - I would check fuses for the power amplifier and other audio - infotainement modules. there are several.
Raanan

 

Ok. Turns out my problem is intermittent. Will do research to know where to look next time it appears.