When I did my EGR pipe (MkIII) I had access problems. I too feared for the rounding off of the nut-heads for a 10 year old car, so I purchased a 6 sided socket set in advance, under the theory that the ratchets sensitivity (intructions said 5 degrees) was a much smaller angle than one twelth of a 12 sided socket (30 degrees).
For 1 of the nut,s by the CAT, I ended up using a 6 inch rathet handle, which had a hole in the end of it, and I tied cord to that and led the line up through the engine bay and gave it a big heave with a "T" handle (made from a torque whrench) [big Sorry to MacRS200]. It was ok and budged. Super wrench above has a hole in the end of the handle too, could be usefull?
Also, often after a nights sleep, things tend to work out better the next day with a fresh mind.
Ring a dealer and ask their advice, you could blame it on a third party mechanic who is in difficulty, and perhaps they will take pitty on you and your pride and joy.
Good Luck & Sleep well!