PSE13 on OS 10.15.7 corrupt and CD installer doesn't work any more.

I've long been using PSE13 on my 2012 MacBook Pro, which has since been upgraded to 10.15.7 Catalina and all has been well. However, I recently installed Adobe CC and that seems to have stopped PSE13 from working. How can I restore functionality? Sadly the CD media installer won't run on 10.15.7.

Maybe there's a more recent version of the installer for PSE13??