Afternoon all

Started up this afternoon, and could near a dull knocking noise from the top. Checked oil, about halfway mark, gave it a little more, started up, smooth idle. Rev it however and the noise picks up and doesn't go away.

Only had this 6 weeks after I had to find another car in a hurry, so "not happy" doesn't quite cover it. It's been spot-on the whole time, nothing unusual, no noises at all, so this has kinda come out of nowhere.

Trying to find somewhere that can fit me in, but no joy as yet, so if anyone has any ideas what it could be, that would be great ta. 2012 TD4 FL2 GS. Totally appreciate that's not a lot to go open, pinning my hopes on a common/cheap fault.

Cheers