Glad you are almost there.
Often that is the value of running diagnostics at home because even if you don't feel like doing the job yourself you can have an idea what the problem is and whether the garage is correctly diagnosing for you.
It is also a benefit of being a member of a forum like this where you have many people with similar cars that may have previously come across the same issues that you have.
Unfortunately, in this case, it seems the garage had less idea than you but without defending them at all you have to remember that they are a commercial enterprise and cannot afford to spend 2 days on a diagnosis that they can only charge 1 hour for.
At least your turbo should be good for a while.
Let us know how the MAF goes.