Looks like someone has chosen to dump some concrete on our land.
Here's a shot of some of the offending concrete - note the white plastic ring on the back one.
And this is a shot of a cabinet nearby on it's own small slab - where there was previously a footpath.
Could one come from the other? Hmm - possibly. Does anyone know what the white ring is for or what this box is actually for? There are no stickers on the side.