GPO Box - Tips on removal?

[#1]

New house, old property (C.1930).  The phone line has previously been GPO which BT have, unhelpfully, not removed and just appended a master socket to at some point in the historic past.  Given awkward GPO box position, I'd like to remove it. 
Q.  Has anyone tried this and do they have any tips/advice?  Any help >gratefully received!

To those who wish to comment that BT Open Reach own drop line and you are breaking the law, thanks for the thought but BT Open Reach stated this wasn't true (BT Open Reach, confirmed 2015) and they are only concerned if you make a mess, I hope I shan't.

[#2]

It might not be illegal but make sure you've got that in writing first as people on the phone are often happy to say whatever is easiest for them.  I ring the dvla yesterday to double check something and they misinformed me. The woman eventually admitted she had made a mistake - one that could have cost me dearly though luckily I was recording the call lol.
As for  the phone line I would suspect you would need it deactivated at the local green box first before playing with it as it carries 50 volts from what an engineer told me moons ago.