Rod Speed wrote:

The plugs thru the tiles pull out with the top screws
with the bottom of the round plate with the screws
thru it acting as a hinge against the tile.

Did you manage to get all of them into timber battens?

Each bracket is secured with five screws:

https://ibb.co/T2dM9xF

On both brackets the top two screws go into timber. On one, two further
screws go into a batten and the final one is wall-plugged; on the other, the
remaining three are plugged.