Please edit the title of your You Should Know post to begin with “YSK”. It’s Rule 1 of the community. Thank you.

Glad you sorted it!

The DeDrm plugin and the most recent Calibre worked for me just yesterday on a brand new book. Something that’s easy to miss is that you need to put in the serial number of your kindle device and make sure you download the e-book for that same device. Otherwise the plugin won’t be able to decrypt it.