The Garage diagnosed the EGR and initially did some cleaning with diesel intake cleaner, which didn't work out. The Garage then suggested that the EGR should be replaced with a new one, but unfortunately the OEM was not in stock by Ford. I then decided to buy a new one from TPUK (which looked exactly like the original one, and the connectors would measure the same resistance before fitting). That was installed by the Garage. It's a mess!