I didnt want to offend you, sorry...in this thread is enough info about a "specialised garage" and "trained mechanic" competence so that's why i was suspicious... i'm just trying to help
if they know theyr job you must be able to tell us what was the maf reading at 3000 rpm aswell to rule out the MAF,
-also important in that hard starting/rough running issue is the fuel pressure after the FPR(fuel pressure regulator, fitted where the the 5'th glowplug must have been) ...a LR garage must have a gauge and know how to measure that
- also what's the manifold absolute pressure?
- does the AAP(ambient air pressure and temp.) sensor show the correct ambient pressure and temperature(compaired to a thermo/baro - meter?)
- do you still have EGR fitted? ...if yes it might be clogged with muck
- What about the glow plugs? ... they have a post heat operation too you know, they're not there just to pre-heat the chamber.
- about the temp sensors... there are two of them, same type and both could affect cold starting:
1. coolant temp sensor(ECT) ..the one from the coolant elbow which you mentioned ...though this one would affect the gauge too
2. fuel temp(FT) sensor(screwed in the FPR) it measures the fuel temperature, if the tester shows constantly 60*C, or you see that the reedings are erratic it means it's fubar'd ... in case of a coolant temp sensor failure the management uses the FT pressure readings
- how are the injector balance/cylinder roughness readings?
how are all these figures on live data? a proper diagnose must have revealed all these readings
....IMO these things are basic knowledge for a LR specialist and for difficult cold start issues they must have checked all
hope this helps