Collected and fitted mine this morning. I fitted it in 30 seconds in the dealer car park.

Called the wife on the way home and she said the audio was now crystal clear.

David. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2012 Range Rover 5.0 SC Autobiography in Indus Silver with Jet/Ivory Interior
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior
2013 Range Rover Sport SDV6 HSE Black Edition in Santorini Black with Ebony Interior

The audio on my bluetooth seems to be back to being crap at the moment.

The microphone is brand new and the only other thing that I can think of is the bluetooth module. I might try swapping it with the other car we've got to see if the fault follows the module. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2012 Range Rover 5.0 SC Autobiography in Indus Silver with Jet/Ivory Interior
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior
2013 Range Rover Sport SDV6 HSE Black Edition in Santorini Black with Ebony Interior