Tubbybear

Hello, I'm trying make sense of an issue that's suddenly arisen with my Audi A4 2.0D Allroad B9 to do with the Adblue. I got a message saying that it needed some Adblue and so I duly filled it up, but the message didn't go away after driving for a bit, so I've taken it to an Audi garage who offered to do a diagnostic inspection. They came back with a long list of issues and fauls with the car, one of which was 'Particulate trap P2002 fault lagged as static'. It also found the 'Adblue pressure too low, suspect a sensor issue inside the amble tank' There were other faults and recommendations listed but these are two in question for this forum. As my countdown clock on the car was now at 150 miles before it's effectively rendered useless I'm being pressured to get this fixed (I'm not even sure how it's legal to disable my car over a fault like this?) However when I asked to go ahead and fix the sensor, assuming that it would resolve the problem, they have come back and said I also need to fix the Particulate trap fault or the Adblue issue won't go away. Cost approx £3500! Are these two things linked, is this a common problem and am I just unlucky that both these issues have just happened at the same time. Can anyone help? I'd love an independent mechanic to take a look but not sure how I go about that.