Minecraft save corrupted since patch

Since the new patch my latest world has been corrupted, meaning it doesn't appear in the list of save games. I lodged a ticket, and a response to the ticket (request #2538843) and have not received a response to my response and complaint. In my response to the initial ticket response I linked an article and asked if it will work. I've since tried using the workaround in the article however even with NFTExplorer I can't open the save files, and without being able to do that I can't find out the world seed which is crucial for the workaround.
I understand level.dat should contain the seed number. I've attached both .dat files. Please tell me my seed ASAP - most of the school holidays have already passed while I wait for answers from you.