AO appears as camera moves

Turned on Use AO in World settings, which I believe bakes the AO with the lighting - but this had no effect. Don’t really want to have to go back to the 3D program to bake AO maps for the scene.
The only solution I can easily see is to shoot wider and then crop in!
Tried adding a cropped video - but this system won’t let me!!!

Anyway - thanks for your help.