The problem we are facing is that of 'Creep' it used to be that the only items that required a Firearm Certificate were those that carried a Proof Mark as pressure bearing items. As a Customs Officer I could not legally seize any other 'Parts' being imported without an Import Licence or in the case of a personal import a valid FAC. However parts might be detained until we could be satisfied that they were not being used for 'Naughty' purposes. However a raft of import and export controls have crept in very often as 'regulations' that have never been near Parliament and this has also crept into the Police view of a number of things. All this of course stems from the 'War on Terror' being used to 'Justify' a lot of very silly restrictions. As Thunderbox says the risk of getting 5 years for being the 'Test Case' is rather high. This is why 'Test Cases' should be just that and should have NO Penalty when they are just being used to clarify the law.
At a tangent (but interesting - to me anyway) how do you determine what an item "is", is evey parcel subject to x-ray, do you rely on the customs declaration ie "metal cup", how do you decide what is a 'suspect item' ?
Mine are not the best, but they are not too bad. I can think of lots of Enfields I'd rather have but instead of constantly striving for more, sometimes it's good to be satisfied with what one has...