With the low volumes Norton has' I'd be staggered if this saved any real money. It only takes one quality issue to cause havoc in his supply chain and wipe out any small saving he was enjoying.
I womder if he's gone 'further afield' due to having burned bridges with European suppliers, as there have been many stories of such ?
As a side note I once had a great talk with a very large TVR dealer, he had just been stripped of his franchise, his 'crime' was that he was offering engine rebuilds with a package of improvements to cure the problems with the Tuscan, this was an awesome car but suffered huge early engine failures (a friend had a new engine after 1,500 miles). TVR said his actions were essentially admitting t faults that they denied existed!
Anyway, the point is, the Tuscan had TVRs own engine (heaven knows why they didn't simply buy something from a big manufacturer) and many key internal components, namely cam, crank, rods, pistons and cylinder head were sourced in Far East. The dealer was scathing about the poor quality. He replaced all these with European sourced parts, apart from the head, which he reworked with new valves, seats and some other work.