Lambda Sensor replacement - is it the right route?

Should be fine with a new sensor - at least you have gone a long way toward testing,rather than just using the parts shotgun !
The type of sensor you need is one of these; Range Rover P38 1999 -2002 4.0/4.6 V8 O2 Oxygen sensor on eBay (end time 16-Jan-11 17:18:26 GMT)
Do like that Africa - VERY nice !

A long time ago...but did this resolve the issue? Ive just had a p1000 fault shiw up on mine...

" P1000 - Lambda Sensor Upstream Catalyst Bank 2 Drive Cycle C .Which has occured once (Signal Missing, The fault is currently present, This causes the MIL lamp activation, The fault has been determined as persistently present)"

So i take it that this is the drivers side o2 sensor that needs replacing?