Workflow plicy not running

Change Workflows are all about the "Workflow options and start conditions"

Can you post a screenshot of yours?

Without a screenshot, my best guess is that your filter is not set on the "Requested Changes" of the Workflow Target.

Thanks both, so even though this is due to run during creation, and the attribute is being set by the sync service during the creation of the object, I should set the condition of the If-Else to be 

Custom Attribute 3 from Requested Changes equals "DCs"

Thanks both, so even though this is due to run during creation, and the attribute is being set by the sync service during the creation of the object, I should set the condition of the If-Else to be 

Custom Attribute 3 from Requested Changes equals "DCs"

Yep. However,  I would be inclined to put this in the Start Condition of the workflow rather than in an If/Else (unless you really need an If/Else for other reasons).