Thanks for replying johnlad, apparantly this has been checked and ruled out, and the current (very bad) misfire is a totally different sympton to when the inlet manifold went originally..just went into limp mode and fault wiould reset itself after switching ignition off.

We have a 2012 LR Discovery 4 3.0 SDV HSE, with 75K miles, we've owned it since 18 months old & 24k miles. The car has been brilliant since owning it, just one gearbox sensor (which packed up on the day LR issued a recall on it) and one mass air flow 6 months ago. However... a few weeks ago, we...