ash, you cant really copy this type of item without pretty much designing it from scratch and making a fair few templates in the process urself. it took me 4 trial plates and many many hours in the shed measuring and drafting up just for the adapter plate, as every hole has to be pretty much perfectly aligned. I'm now 1/4 way through the first run for the main caps/adapter plate, and this one has to be even more accurate.
Yes there's alot of man hours gone into a thing like this, but at the end of the day, if there's people wanting them, why would workshops turn them away if they know they are going to make profit on them.
But anyhoo, i should have my first girdle back from the machinist in the next 2 weeks.