Dav, I understand better than anyone how frustrating it can be when such a fantastic product doesn't quite come up to operational expectations. I too found myself in a similar position to you and I was frustrated because what I was hearing was simply fabulous. The resulting negotiations did not go well so in the end I bit the bullet, sent the BM back and bought a Rega DAC. Had the issue been sorted to my satisfaction I promise you the BM would still be in my system.

Everyone handles such situations differently and I am big enough to admit that perhaps I could have been a little more diplomatic. Despite this I would still say that the Bushmaster is the best sounding DAC currently retailing at under £500.