VAT regarding My FBA has been stored in PL and CZ


I have VAT numbers in the main EU countries but as i found out that i have FBA inventory being stored in PL and CZ, i know i need to register for VAT in those 2 coutnries too.

Now i need to know since WHEN the stock was in these countries so that i can register (its one of the first questions of the registration)

How can i find this out please? I cant see where it would tell me this - We had PAN EU for some short time, before i think it ended - im not sure?!

Thank you