If something like this can be made in the UK for that price point and still turn profit enough to make a living, it says a lot about 1-3k IEMs. Particularly ones made in China using a slave wage economy and in constant production.
He did move some parts on house. Time for some speculations...I thought Bob said after the **** ups with the Z he was moving production on house?
That means he probably imports the basic drivers, cables and accessories from somewhere and assembles it himself (to prevent wiring disasters as with some of the Zeniths). If he got the industrial equipment to produce the housing and filters himself... no idea, but i could imagine it. The anodizing might also be done in house, since he slightly changed it from model to model (maybe some remember the serious discoloration on the original R1).