HI Vegemitesandwich,
I don't know if you ever got the parts you needed. But, Grizzly has carried a number of the Sieg Machines and is an excellent source for parts, often at a lower price that LMS. The G0516 Lathe/Mill combo, has the lathe portion I believe from the same C4 Family of lathes. I even believe they once carried the C4 lathe on its own, but I can't find the old part number. I've found Grizzly very often still carries parts for the machines the no longer sell. You just need to find the Grizzly Model number and search for it on the Grizzly site, which will bring you to their "discontinued" page, with the option to purchase parts at the bottom.
Hope this helps,
Chris