I’ve noticed just recently that when the engine is running at idle there was a very annoying, metallic rattle emanating from somewhere within the engine bay. I managed to have a look in there today and check for the suspect component. Eventually I traced it to the turbo heat shield. There was a bolt missing from the rear of the guard, as usual it was nice and awkward to get at! After much fumbling with various bolts, I found the thread to be M8. I’ve replaced the missing bolt with a stainless steel one I had, adding a good dollop of copper grease to the threads to aid any future removal. Access was very tight, with the access hole being very near to the bulkhead, eventually a 13mm socket on a 1/4″ drive extension and ratchet did the trick.