hi Richard,
thanks for the link, to me this one appears to be a generic Hughes in a Japanese case but when I look closer it says "Case made in Switzerland" which is uncommon.
Unfortunately I don't have one like this but please measure the diameter of the thread and maybe somebody will have one at hand.
on FB...I'm not getting messages on new posts for some reason.
just had a look and the case could be hammered back to some extent and rebrushed however the hole will still be visible.
laser welding is to expensive although would come practically unnoticed.
if you need a magician with super expensive tools and machines in the UK please check this link:
http://www.watchworks.co.uk/index.php/about-usa fully restored case costs roughly 300$ and might vary and I have seen completely trashed Rolex and Omega cases that this guy restored to NOS condition with laser welding and factory starburst brushing. it makes sense with a 1000$ so not so sure if it's affordable for cheaper makes.
you can find various posts from happy watch collectors on WUS.