I’ve since found the solution thanks to an X70 shooter on a dvinfo.net forum. You have to go into the folder structure and delete the XDROOT folder (providing you haven’t used XAVC CLIPS), et voilà , the clips now appear.
Movcam is the name of a brand of camera supports. Part #3032702 is a baseplate for the Sony FS7, which records in Sony’s XAVC format. If that’s the camera, you’re right – you will need FCPX 10.2.2 to handle XAVC video clips.