All sorted now gents...........

Tried the headlights when I got home - nothing.
Then checked the + and - terminals were both tight which they were. What wasn't tight was the connector on the + terminal going to the bulkhead, whatever that's called !! Tightened that up and voila - all working again. I can't believe that the nut has worked loose so I can only assume that I didn't tighten it up properly when I changed the battery last month.
Thanks for all the suggestions - note to myself.........double check all connections when reassembling  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

Nice cheap solution.

Aye ye canna beat tight nuts

Indeed you can't 47p2 - also helps if you smear on some Vaseline apparently  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

No need for vaseline in Ayrshire