Composite input problems on 2407?

Been using this monitor successfully for a few months now and im pleased with it. However a few days ago I tried connecting a variety of my old game consoles up to it via Composite Port. They are all PAL format but as far as I am aware the monitor should support 50hz via composite.

Basically the screen flickers a lot and it looks like it has detected a signal but refuses to display it. I tried various consoles, dreamcast, saturn, playstation and even my amiga to no avail. There was a display from the playstation ( the boot interface ) but as soon as a game boots the display goes back to black flickering again. Please put me out of my misery and tell me it doesn't support these inputs or if it does, what im doing wrong?