So maybe after all this it may have been a coilpack?
Sounds like the garage definately knows what its doing
Even I would have changed a coilpack before a spark plug
Did they even scan it with VCDS? That would have told them what cylinder the misfire was on?
You have been given good advice on where to go from the likes of Alex, PDT, R-Tech its now your choice.
But why would you listen to me as you have not bothered with anybody else with 4k plus posts!
Good luck as you will need it!