FM Radio Wiring - New Zealand x5

[bmwx5nz]

Could anyone point me in the direction of the radio antenna wiring diagram for a 2002 X5 4.4i.
I've had the spare tyre in and out a couple of times lately, and my FM radio reception is now very bad. I assume I've knocked something in the boot.
I've had the cover off (located on the rear inside window, and have checked the connections to what looks like a FM booster? however unplugging these did not seem to effect the reception at all.
I've read in other thread's that the parts I'm looking for may be lcoated in the driver side rear wheel area, or under the spare, but don't know what I'm looking for?
Thanks