Success! :thumbup:
With the help of the forum I have managed to successfully install the car kit without suffering a complete nervous breakdown. Thank you! Now, for the benefit of others who may read this in the future, here are some tips......
* UK Spec cars do not come with the telephone preparation wiring loom as factory standard. If you were sensible enough to order this option when you bought the car, then fitting a phone car kit will be a relatively undramatic affair. Just remove the central kick panel on the passenger side by pulling hard nearest the front of the car and you will find the connector under the central storage tray.
* If, like me, your car does not have the phone prep wiring loom, then you have my deepest sympathy and please keep reading.
* Depending on the make of the car kit, you will most probably need to source 4 wires; Ground, +12v (permanent), +12v (ignition switched), and Telephone mute.
* If you have a CDR-23 radio/CD player in your car with the BOSE / MOST system installed, then you will not have the +12v (ign. switched) cable on the back of your radio. Don't bother looking, you'll be wasting your time and you'll only end up grumpy. The cables you DO have are most likely these:
Pin 1 - Speed Pulse (for the speed dependant volume control feature)
Pin 2 - No idea, but if it ain't broke.....
Pin 4 - +12v (permanent)
Pin 5 - Aerial amplifier remote
Pin 8 - Ground
* If you don't have the phone prep cabling option installed on your car then the telephone mute wire (yellow/black wire) will not be present either. You can tell by checking pin 3 of the "A" ISO connector on the back of the radio. You will need to add another connection to this pin if you want to use the mute feature. As per normal for this feature, pulling this pin to ground will mute the radio for as long as the connection is maintained. "PHONE" will appear on the display of the CDR-23.
* Ground wires on the Boxster are brown and can be found all over the car. I used the existing wiring loom for the radio (CDR-23) by tapping into the connection on Pin 8.
* +12v (permanent) is also readily available behind the dash, but I used Pin 4 on the same ISO connector.
* +12v (ign. switched) can be taken from the fusebox without too much trauma. As Loren correctly advised, it is a green/black wire runnning from fuse E8. Remove the fusebox lid and you will find 4 black screws at the side of the fusebox. Undo these and the carpet / trim panel can be removed. There is a single screw about halfway up the fusebox on one side that allows you to remove the whole fusebox from the bodywork. Remove the plastic cover on the back by gently prying open the four clips on the side. The back panel will come away completely and allow you access to the cables on the back of the fusebox. Locate fuse E8, and the green/black wire runs parallel to the main wiring loom, but is separated from the others (very convenient actually!) Tap a feed from this wire and run it to your phone car kit.
* I found that the car kit could be conveniently located behind the central storage trays, along with the speaker (if you are using one). The microphone sits quite well on top of the speedometer (under the arched trim piece at the top of the dash). To make it easier to run the microphone cable neatly down to the phone kit "brain", remove the rev counter / speedometer dials which exposes a few cable channels leading down behind the dashboard. This can be done by prising out the hazard light switch on one side, and the small circular microphone grill on the other. There is a screw behind each of these which holds the instrument cluster to the rest of the dashboard. Once the screws have been removed, pull the instrument cluster upwards towards the screen and they'll come out quite easily. None of the cables need to be disconnected, you should have plenty of room to work.
* My original plan was to hide the phone car kit microphone behind the microphone grill on the instrument cluster. This is not possible if your car has the BOSE sound system, becase this grill actually conceals a genuine microphone which is used by the noise cancellation "Sound Pilot" system in the car.
I hope that this helps people in the future. Share the knowledge and all that..... :cheers:
regards,
Rich