Just going online to brownells, and haveing a hammer or trigger from a pietta saa sent to an address in the uk would be enough to gt you in jail.
Actually, US legislation is such that US companies are prohibited from shipping anything that is part of the gun.
Sights, not allowed, Optics, not allowed. I've tried, and that was the reason given. Holsters and grips I have managed to buy but not the others.
It seems that Estonia is listed as an undesirable state to ship "strategic" goods to.
Estonia is an EU state, part of the Euro zone and part of NATO with, proportionally speaking, one of the highest numbers of troops committed in places like Afghanistan etc. But hunting optics or scope rings? No, we are too dangerous to supply...
So, the idea of ordering a trigger to the UK is a non-starter...