Does "Garden Law" actually exist?

[GlazeAway]

Hi, just wondering if anyone can advise me? We own a victorian mid terraced house and in our back garden we've installed 6' fences and concrete posts on our side of the boundary wall which separates our garden from neighbours each side. The original fencing was installed back in 2010 and previous owners next door dismantled the little boundary wall on their side as it was crumbling. They asked us if we were OK with it and that was fine. Although there's still the 6' original boundary wall in situ a third of the way along and still strong. The fence was installed on our side of it. They had a small child and it made their garden safer. That side is to the left of us as we look out the back door. The fence on the other side, on the right as we look out the back door was replaced by us back in the winter following stormy weather bringing part of (neighbours) wall down in our garden. Again we had 6' fences and concrete posts installed on our side of the now knee high wall, so within our boundary. In doing so we've lost a few inches either side but have our privacy and it does match on both sides.
My question is, although we've paid for it (receipts to prove it) and it's on our land. Do they have any rights to paint or attach anything to it? I've read that they don't but others have conflicted this and think they can do what they like their side? We had words with one side last year as they went ahead and ran a power cable along the top and nailed several lines of lights along the top. They know the fence is ours as we have replaced 3 panels since they arrived (they rented house a few years ago) and I just popped around to say Hi and explain that the panels were being replaced and as they had a dog, please keep him in for 30 mins to stay safe whilst the panels were swapped over.
Appreciate any advice. I don't want to fall out with anyone but don't want cheeky people thinking they can do what they like to our property.
TIA

I think confusion often arises when there is a responsibility for a boundary and then who pays for a fence. There is no legal requirement for a fence on a boundary unless is specifically states this in the title deeds of the property. I am in my 5th house and mine specifically says that all walls and fences must be kept in good condition and/or replaced if they come down. The boundaries are all shared responsibilities on my estate and any repairs we have gone halves on with the neighbours. On no other property have I had that stipulation.

The fence belongs to you as you paid for it, even if it is on a boundary that is the responsibility of the neighbour. Legally they are not allowed to paint it, grow anything up it or attach anything to it as you paid for it. What I would say is I would be concerned over damage to a fence caused by a neighbour but honestly, I would let someone paint their side of any fence I bought.

We bought two sided fence panels meaning my neighbour can paint their side of our shared fence and it won't bleed through. We did this deliberately because they have a different colour on their other fence panels in their garden and it is different to what we would choose. Some people still go on the if it is on your left it is yours or if the post are on your side it is yours bollocks. Only the deeds denote responsibility for a boundary and fences if not shared in cost cannot be touched.

In your situation if you don't feel you can do a face to face, I would do a polite note explaining that the fences were bought and paid for by yourselves and could they please ask permission to paint or attach things to the fence. I would word it so it looks like you would say yes to reasonable requests. I would absolutely want to know if there were electric cables of any kind just for safety reasons.

Technically they’re not allowed to touch your fence. Of course it depends how bothered you are about enforcing this.

Thanks for your replies. I went online some time ago and downloaded a basic Deeds search for the property but it didn't confirm ownership of boundary walls either way. Just a red line around the perimeter of our property. That's why we had the fences installed on our side of boundary walls.

If you paid for the fence it’s your fence. Even if the deeds say they own a particular boundary, that doesn’t mean they own your fence.

They can't do a damned thing to your fence unless you agree.