FreeAgent's Active Sessions
FreeAgent has an Active Sessions page where it lists all the place you are logged in to your FreeAgent account.
When DoubleAgent accesses your FreeAgent account, it will naturally show up on FreeAgent's Active Sessions page. However it won't be listed as DoubleAgent; instead it will say airblade factor-0.1.7 (the numbers could be different).
The name comes from my company name, AirBlade, and Factor, the software I wrote to talk to FreeAgent's API, which DoubleAgent uses.
Feel free to click the Log Out button to log out DoubleAgent. DoubleAgent will log in afresh the next time it needs to.