B&O Beogram CD-50

I have B&O CD-50 which would not eject, I've replaced the rubber band that drives the tray cogs which has fixed the tray - discs now load.

Disc however will not play - I can hear a clicking sound coming from the mechanism that hoses the laser and motor. Eventually the disc is ejected.

Does anyone have knowledge of how the disc loading works? I can see that when the door is closed an arm below the disc lifts the disc up, before dropping slightly. I'm not sure if the disc should be picked up off the tray to be spun - if it should be I can't figure what keeps it off the tray?

Thanks.