Think there's some thing missing, fluorescent lamp 'A' level.

[Harry Bloomfield]

The units I refer to looked something like this:
View attachment 190327
The metal arm was maybe 1/2" square and the box in the middle maybe 3 to 4" square and just thick enough to take the starter and connecter. As has been pointed out to me by my sister our original kitchen fluo was the same design but mounted on a bayonet plug and it was never square with the kitchen or level.

Trick was to add pennies on the end which was high, to get them to level.

 

[SUNRAY]

Trick was to add pennies on the end which was high, to get them to level.

I thought pennies were for record players.

 

[bernardgreen]

I thought pennies were for record players.

and for the pendulum in Big Ben