Dave Plowman wrote:

I have a TV on a longish arm(s) in the kitchen. Allows it to be swivelled
to use when cooking, or when eating at the other end of the room. The arms
are long enough so the TV can be pivoted up against them - ie at right
angles to the wall.

That's very similar to what I'm planning.

It is mounted using rawlbolts into plaster over brick. And the arm gets
likely more use (movement) than many.

That seems the best way forward for me too.