Disconecting External Power, Externally?

Sorry. I really couldn't think of any other, succinct, way of posing it

Here's the thing: They installed a wire down to my stables. It's an overhead. It feeds mains power to a light and two plug sockets down there.

Every Year my neighbour wants to run tractors 'under' that wire, for one day as he harvests. But, lest one not 'fit', he has me switch off the mains. Then he disconnects at the box down there and puts the wire aside.

He doesn't always 'think' to pop back that evening and put everything back. Either way, I've come to realise the mains power breaking costs me a light bulb, most times. Either way, it stresses me the f out! It's just a PITA.

Obviously, a far from ideal situation on so many levels. So, I'm just wondering: Is there anything I can do (Have done!)? Ideally, a simple, external disconnect outside the stables. A 'plug' he could pull. Then plug back in at the end of the day.

I ask that because the wire we're dealing with threads through the stable wall. Any such plug, inside, wouldn't. How could he remove the overhanging wire then? See?

Sorry I had to write so much. Just trying to make the situation clear from the start. And, Yes; I'm completely aware that this would be a job for a qualified spark. I hope to last another decade and I'll pay to be rid of this annual event.