L322 Diesel engine fault

Hi there, just wondering if anyone can help with a strange fault. 2003 RR HSE runs great as long as you dont take the revs over 3000 rpm. If you do give it some stick, when you slow down the engine is missing and vibrating as if it had a duff plug or lead. Knock it off for 5 mins and it's fine.
Do diesel injectors play up before they die or just fail. Motor has done 67k miles and the only other fault is a cloud of blue smoke on startup when first started, which smells of unburt diesel not oil.

Any help greatly appreciated.

Yes,TD6 injectors are well known failure points - as in TD4's.The way to find out whats wrong is to get it on Testbook and look at cylinder compensation values in live data.This usually makes a clear picture as to whats wrong,if it were a low,low side pressure issue it would probably have poor starting issues as well,so injectors sound more likely.
Not a difficult job to change them as long as they are not carboned up in the hole they are clamped into.They dont need coding and are available as service exchange units from LR or aftermarket.