UK Car Repair Questions? Ask a Mechanic for Answers ASAP
Hi I would go with the EGR valve and if you don't want to pay £300 on a gamble you can try blanking it off and running the car with it blanked off for a while. If the fault goes then you will need a new EGR valve and they are very common to fail on these cars and cause a loss of power.
If it was a problem with the exhaust valves you would get a misfire fault code coming up and not a EGR valve fault code come up.
I hope this helps