Sue on a Defender there is a Nut plate that has a clip that clips in. I usually change these at the same time as the bolts because they do rust. and sometimes seize. So the nut plate should be there however if you have trouble it may have moved out of position or its rusted and needs changing
Thanks The bolts appear to be turning when I put a socket on the top bolt, is that all I need to do or does this nut plate need holding