Had an interesting chat with A&S Firearms dept today. I have just got my ticket back from its renewal having requested that my 243 Win space be listed as 6mm. This was requested so that when I get my Sako rebarrelled to 6x47 lapua it would be legitimate on my ticket.
The ticket came back with 243 listed again. I called the Firearms Dept to ask if they made a mistake and whether they could do the change. The reason they gave for not making the change is because every time a rifle has a proof/reproof for a part replaced (ie not threading the current barrel), the owners FAC must go back to the licensing dept for approval...
Even if you get your barrel replaced in the same calibre this is still the case.
I will have to put a variation in... another 2 week wait then