"Mike Lyle" wrote
So let's consider psychological warfare. I wonder what would happen if
whenever they showed up you went out and joined them sitting on the
wall with your mug of tea, and told them all about when you were their
age in excruciating detail, preferably with much repetition, and maybe
a few asides about the state of your health. It would then be your
turn to enjoy a wind-up, and they'd probably avoid your place ever
after.

I like this idea (posted not just by Mike but a few others).

I think the only problem is that, for some people, this might require some
dedicated acting. I know for me, acting out of character for more than a
minute or so is very difficult.

Still, it's worth a try. I'd number it 1, followed by the anti-burglar paint
(love that suggestion about mixing motor oil with ordinary paint, btw,
though I'm not sure that is very long-lasting once on the wall), followed by
putting something on the wall that makes it uncomfortable to sit on,
followed by a little legal action.