John
UK laws are not usually made respectively unless by an act of parliament they usually come in to force on the day that they are past or enforced.
So your gun with no proof at all so long as it was made before the date the law was put on the statute that is fine. This is the reason we have motor vehicles on the road that do not have seat belts flashing indicators or brake lights because they where manufactured before the relevant laws regarding those things where passed by parliament.
But there is always a but here in the UK when it comes to Tort laws just as an example Civil Tort could argue the point that because a gun has no proof marks the owner should (point of law to be argued) do all within his powers to see that the gun he sold was perfectly safe, so it could therefore be argued that the gun should pass through the proof house system to prove this fact. What I have just said may not ever happen at all but if you get a lawyer who will take your money and try to prove the case at your expense though it could go all the way to the House of Lords if you have the millions to spend.
As they say the Law is an Ass as well as being blind. And Lawyers really never loose financially no matter what the outcome of the case.
