Mine works tickety boo with my Sony Ericsson HCB300 car kit.
Can't see why it wouldn't work with most bluetooth kits - I think that the Pearl uses the newer version of Bluetooth but am not sure if it is completely backward compatible.
I had this problem when I went from a Moto V3 to a Moto V3i and my older HCB30 the V3i wouldn't connect automatically so I had to upgrade. Managed to get hold of the newer HCB300 from eBay for around £40 quid so just had to change the hardware box and the call switch thingy I didn't have to worry about changing the Mic.
Probably the best idea is speak to your local Range Rover dealer to find out what you need then get looking on eBay!
How old is your car and is it a manufacturer supplied car kit?
If it is more than a couple of years old you may have to upgrade.