It's simple to check if a BankID signed document is valid and to see who signed it in Adobe Acrobat.
A green check mark in the blue field on top means that the document is signed.
Click Signature panel to find more information about the signature.
The Signature panel shows you who have signed the document.
If you click Certificate details, you will get information about all details in the BackID certificates of the signees.
Here you can see several certificate details, inculdig to check if the signature validates against the EU trust list.