Need help with archival search

Hi, during the WWI my great grandfather spent four years in captivity working on this property that is currently turned into a nice guesthouse.
https://www.booking.com/hotel/cz/villa-klimetice.en-gb.html?label=gen173bo-1DCAsoOkIPdmlsbGEta2xpbWV0aWNlSDNYA2hSiAECmAExuAEJyAER2AED6AEB-AEDiAIBmAICqAIDuAKhz-CPBsACAdICJDRkODdhZDk3LTY1MGYtNDlmYy1hNjEzLTM0YzFiMmYxYzBkONgCBOACAQ;sid=8fe03c48b1128ce05d172eb39fe63dce;dist=0;room1=A%2CA;sb_price_type=total;type=total&

I plan to visit Prague and spend a day in this place too and I want to enquire if the current owners of this property are the same family my great grandfather was working for. Maybe they have some old photos or other materials from 1910s. I can’t find the direct contact of the owners of the guesthouse.

Maybe you guys will have some helpful tips how to go about this search? maybe a local archives can provide some information? Will I need special permission to ask for information from archives? Unfortunately I don’t speak Czech language and I couldn’t find anything online in English.

My great grandpa sent a letter and a few postcards from this place and even though he was a war captive, it doesn’t seem like he was being mistreated from the family so I would love to find out more about that period if possible.

Thanks a lot in advance.