Thanks for the reply!
In this case BBoxtop is going to give me the same result as Y, so those could be interchangeable. The origin is the top-left of the Tiled Background, so regardless of angle both will be the same. The image is just to show how I currently check if the player is on top of the tiled background, and how that doesn't work if the object is angled.
I did consider your approach of using "overlap at offset", but for reasons that are too long winded to get into here, that's not an option. Asumme that the player object we need to check for is possibly always overlapping the tiled background, and is large enough that we need to be checking a specific point rather than the collision data of the player object.
Now, the easy way to do this of course would be to pin a single pixel object to the player at the correct relative location for the check, and if I have to I will do just that. But I'd really rather not as my player objects already have a lot of pinned objects I am keeping track of, and because my player objects are also enemy objects there are a lot of them in each layout, so adding this overlap checker object can add a lot more objects to the layout.
I'd really rather use some math on the check to determine if the relative point is empty or not in other words.