We have neighbor kids who think nothing of entering other people's yards through the gates to get their tennis balls from playing cricket in their postage stamp sized back yard! Despite there being a 25 acre park across the street from their house!
I caught them in my yard at night, and all day. Once came back from a walk and caught them letting themselves into my yard.
I looked at them and said EXCUSE ME, who ARE you and why are you entering my yard?? (oh, did I mention that they have lied to my face and told me DH said they could enter whenever?)
I have told them over and over to stay out. We have a dog and they never close the gates properly.
Finally DH went and talked to the Dad. As did my neighbor-who was afraid of his kids getting out.
Just yesterday, I watched him hop over the 6 foot fence to get yet another ball next door.
Some kids don't care.
I would march over and explain that the kids broke your things--and tell what they were and the meaning to you. Tell them you would like them to pay you for the things. And if you see their kids in your yard again, you will be contacting the landlord. Because really- they seem pretty clueless to me. Since they don't care if the light was an accident. I would still have offered you money or gone out to get replacements.
Since they didn't, it suggests to me that they don't care.
So if you don't tell them up front what you want, they won't do anything for you.
And just in case they don't know, I would remind them that if those kids got hurt on your property, you could be sued.
I would also think about getting one of those low, white plastic border fences (usually used to border gardens, or to stop people from trampling saplings etc.
JUST so they are reminded where the line of demarcation is for the yards.
I'm pissed for you.