Happy to say problem solved. Naim provided a replacement set of Burndies to my dealer in short order, ie quickly, and they fit exactly as one would expect, locking with a firm, smooth ‘snick’.
What’s interesting is that because the new Burndy connectors fit as they should, the others must be slightly different, perhaps slightly incorrectly made. It seems there may be some QC learning for Naim here.
And, of course, the prompt replacement implies Naim must already know about the issue, but that it’s sufficiently uncommon that the whack-a-mole approach will prove adequate.
Quite where my dealer’s design change reversal rumour arises I have no idea, perhaps it’s seen as a better story than a bit of iffy QC .
You’d think it would be really easy to test the Burndies for fit before putting them in the box, but who are we to say? As the saying goes, they should just work. Anyway, your problem is resolved. Hurrah.
At my home demo today my dealer had difficulty removing a Burndy from an NPX 300 / NSC 222. Interestingly, they went on quite easily. I suggested he just leave these boxes with me .
I have found that my S-XPS Burndy can be quite difficult to lock the rings if there’s some twisting or torsion in the cable itself. Other than that it’s usually just a firm grip and twist on the connectors with the cable in a fairly relaxed state.