The car & spanner symbol had started coming up, ever more quickly after start up. Having been down this route a few months back resulting in my installing a s/h EGR valve I assumed that this had failed and forked out for a new one, fitted it this morning and found no improvement. Somewhat fed up I came back to the forum and read up on the P0093-52 fault that was being thrown up, this led to my deciding to top up the fuel filter through the bolt hole to see if there was air in there, there was, a lot. I started topping up through the bolthole and then noticed diesel was coming out from the back of the filter lid, I decided to change the filter at this point (<5k since service). I took the old filter out to find lower half was fairly dirty, probably as I'd put some injector cleaner in, swapped filter out and have just been for a blast, no spanner light & performance restored, looks like I might have spend £150 on EGR prematurely .