Also very interested in this post, in particular whether cleaning/replacing injector(s) (car under warranty, and not had 1st service yet) will reduce the clattering sound from under the bonnet.
I took the car in for the dealer to have a look at, his official view was..
well we plugged it in, and can't find anything wrong, so we topped up the oil..
He suggested I used redex or similar, but FFS it's not an old banger, I shouldn't HAVE to use an additive in a modern car. (ok, I have tried it, but makes no difference anyway)
Am waiting for service, but still got nearly 3000 miles until it's due. I'm planning on taking the car to a specialist for this (rather than dealer) but obviously concerned that if they find something, the dealer is then going to be reluctant to fix the fault under warranty.