Hello, iv'e discovered a small covered bung or plug on the outside of my house wall, i may have only really just noticed it but i have no idea what it is as it seems to just sit in the stone brick like a covered raw plug type thing, its about the size of my small finger nail, had a black cap with a white washer around that and looks to have been pushed into a drilled hole, is it anything to do with an old satelite dish or telecom object, there are no wires from it externally, it's really vexing me, does anyone know plse