The clips are all there and fitted properly.
You will see daylight through that type of system, fitted thousands but not on slate.
It's not fitted properly....
and it would look the same on tiles with the way it was done. The unions should not be pushed down like that.
https://gyazo.com/b15b97227ed6a6e06748ee7a39751d3f There should be a clip in the middle like this (should have a screw hole though) that holds up the union.
https://gyazo.com/703c3154a5f12c576cb8c33b0cca6901 found the correct clip that goes on the union