i have a pegeot 206 with a knackerd bosh brake compensator would a bendix compensator fit and work

All l know is. if ur rear brakes have TWO compensators, as many Peugeots have, both compensators must be of the same type. TWO compensators r found on Gti models at each rear brake. ONE compensator is sometimes found in the engine compartment.
They have a fixed calibration from the factory.

Also, the mounting bracket for ur ''ONE compensator style'' has a specific angle to it. The angle ''inclines'' the compensator upwards at 22 degrees to the horizontal (just for an example). This may differ between Bosch & Bendix. l am not sure. Try to notice this difference as u remove the Bendix from one car. to add it to the other car.

Yes, they are essentialy the same make according to Peugeot. Likewise ATE and Teves systems.