Answer
Create a shortcut on your windows desktop for the TdkSmUpgrade executable and then right click on it to access its properties and modify the target field to include the word “force” at the end as below:
“C:\Users\mark.duncombe\Desktop\TdkSmUpgrade_v4_2_2.exe” force
Then, when you run the executable from the desktop shortcut you will be able to load a firmware version earlier than the currently loaded version.