Yes, i have the patch installed. I thought i might have installed it in the wrong directory, but it wasn't the case.
I returned to the mines a while later, but the bug was still there. What i could try is checking for the time of day, since it's logical when they're gone at night.
I will try your other suggestions, although i haven't seen the items at the shopkeepers myself. But then again, i never visited them much. I suppose i'm pretty stuck on the machanised armour though, which is a shame. Let's hope it's just the time of day that's the problem.
Thanks for the reply though. I was starting to think this would be ignored.