Talk to your dealer first ....
We are now investigating this situation. After discussion here we think we can synthesise the mark you have on your cabinet. We going to experiment and report later.
Members here should appreciate that whilst they have a direct channel to me through the Harbeth User Group, as a matter of contract law and courtesy, your first point of contact is with your local supplier. He or she is capable of resolving almost every issue and concern. All Harbeth dealers strive for happy repeat customers. Discussing any matter or concerns with your dealers first will definitely speed-up the resolution.
Alan A. Shaw
Harbeth Audio UK