Not quite sure if you've managed to figure this out, however please follow below steps:
Resetting the Limited Rares page
1) in Navicat go to table catalog_pages and look for 'Limited Rares' under caption and note the id of that page (i'm sure it's usually 16 but double check this!).
2) now go to table catalog_items and CTRL + F and search for the value you found in the previous step and search for the value under page_id.
3)Once you find a page_id of that matches scroll right until you see limited_sells & limited_stack they should both contain the same quantity as they're sold out 800/800.
4)Change the limited_sells value to 0 and that will reset how many have been sold. Change the limited_stack to how many you want users to be able to purchase.
5)Let me know if it works!
Sorry for the bad help! Bare with me it's my first time!.
If you need a bit more in depth help just give me a message and I will help out as much as possible!