I haven't noticed any  exceptional oil consumption on my 120000miles J
reg Trooper. However the oil pressure when warm seems very low ( less
than 12psi  but normal when cold) apart from the usual valve seals,
could oil be leaking from the Turbo. Not letting the engine idle for a
couple of minutes after a brisk run along a motorway can lead to early
failiur of the Turbo oil seals. Sorry not a great answer but again my
Trooper hardly uses a drop of oil. not bad for an old girl.
regards
Keith