The crankset arrived back from Middleburn today.
No explanation given, but the granny ring now sport some 1.6mm thick alloy spacers between the ring and spider.
Will refit and try them out at the weekend.
Seem to remember, I had exactly the same problem with a Middleburn set of rings a few years back too, Ironically on a Clockwork.
It was the offset on the Middle ring, if you look, they are extremely thick and the chamfer from the teeth to the bolts is so sharp it throws the ring off, so much so that it misses the granny ring altogether.
I fitted some Race face ones and they shifted perfectly.
The lack of explanation smacks of "Guilty as charged M'lud" I would bet if you replaced just the middle ring with a narrow ring from another manufacturer such as TA/Sugino or Shimano, it would work.
Having to fit a 1.6mm spacer is certainly non standard practice!
Live the dream-Ride on!