Thanks Ricky the p-bus white connector was exactly what the problem was - the little securing clip ring was broken so it wasn't pushing the switch fully home. Bought a complete drivers door loom from ebay for £20 and swapped over the clip ring to the car switch and bingo - all sorted.

cheers  2017 4.4 TDV8 Autobiography
2016 4.4 TDV8 Autobiography - GONE
2013 4.4 TDV8 Autobiography - GONE
2010 3.6 TDV8 - GONE
2008 3.6 TDV8 - GONE
2002 3.0 TD6 - GONE
2006 Discovery 3 TDV6 S - GONE
2006 Discovery 3 TDV6 - GONE
2003 Discovery 2 TD5 - GONE
1999 Discovery 300 TDI - GONE
1998 Range Rover DSE - GONE
1997 Discovery 300 TDI - GONE

grand stuff