You can get a new cover from Ford or search a scrappy. On mk1 I think there is a seal which you need to change as the old seal should never be used again. But sound like the cover a seal are just there doing nothing. So I would replace them but get a new seal not one from scrappy.
Ford already tried that. They disconnected battery. Tried using there diagnostics and all the come up was the GEM not responding. They even tried connecting my old gem and old cluster that didn't work. Tried copying my setting from old gem and putting it on new one that didn't work. Ford are lost on what the problem is. The gem having issues makes the airbag module have issues. Ford sent sure if there is a fuse to the gem itself. They printed a gem wiring diagram for me. So I'm going to check all the cables are connected fuses etc. Wish me luck.