disconnecting V6 boxes

 Help!

Two of my three V6 boxes will shortly no longer be needed. VM said, when having given them the serial numbers of the two boxes in question those boxes will be disconnected at VM's end and I'll  need to disconnect their cables from the rear of the boxes and include them in the packaging. Neither of these TV boxes have the 'white' 'coaxial' ( or whatever it's called ) cables fitted to a 'wall box' so I cannot just unplug them.

From what I can see the white cable comes into the house through the wall and meets a 'double ended' metal cylindrical piece  (just one has a rectangular metal piece marked 6Db ) with hexagonal nuts at either end and marked ' cablecon 3.9' then a further metal connector, also with a nut a bit higher up connected to a shorter cable pushed into the rear of the box.

I'm quite unwell at present and was never very technically minded and also can't find anyone able to physically help me. I am finding difficulty understanding how much of / which parts of the cable need to be undone ( presumably with a spanner ) and returned.

Thank you all again

Steve