I had exactly the same problem with an Atlantic X105 (the only one I ever had a problem with). I sent it to Dublin but didn't hear anything for a while. After some homework I discovered the person to contact was:
Glen Whelan - Customer Support Manager
His direct email is:
Glen@peterson.ie
If you would rather send back to Peterson that is the person to do it through. Following an email to Glen things started moving and within about a month I got my pipe back. It is fine now - the high glass finish was removed and it is now more of a silk finish.
Alternatively, good luck with your search for an independent finisher.
In any event, perhaps this info might be of use to another Peterson fan who has a similar problem.
Mike