Your welcome :)
its worth replacing the relay. But like you I'm unsure if there's a module.
As long as the dpf isn't nearly full it should do the Bergen ok once fixed :)
in terms of the egr and egr cooler, replacing them is an expensive job. You'd probs be looking in the region of £1000. When I worked at Volkswagen in the service department it was common of VWs to come with this problem. It was mainly the 1.6 and 2.0tdi which were common.
Cheers
steve