I'm not a mechanic but I know that ECU's log faults that subsequently clear and cause no further issues. The ECU logs them with a date and time and mileage so it can be determined by a competent garage mechanic if these faults are associated with the problem you take the van in for at a later date, if the van has never been read in its life then there could be loads of logged issues that have never manifested into service affecting faults.
Without a direct read of the ecu and a log of the mileage against the fault logged you will be unable to determine if any of those faults are the cause of your issue. Just having the P code and description is not enough to say that any of those fault codes are either pertinent or current.
As a minimum I would have copied the first read of the ECU, cleared the fault codes and then run the van to see if any of the codes returned.
If you didn't have the MIL light lit (check engine) then I would say that none of the codes were pertinent in the cause of the issue you have.
Have they now cleared the codes from the ECU (bet they have) and have they kept the date and mileages when those fault codes were logged (bet they haven't).
If the P056200 fault was logged 3 years ago, it is not a factor in your current fault.
Is the van running now? Has the adblue range come back up to normal?
This is why I don't trust garages with anything more than an MoT.
