If you need to disconnect, you can do this in the Making Tax Digital for Income Tax settings window.

This option clears all associated credentials but retains your Income tax categories. 

How to disconnect

1. Log in to Sage 50 as Manager.
2. Go to Connected services then select MTD for Income tax Settings.

This opens the Making Tax Digital for Income Tax Settings window with details you entered during the set-up process.

3. Select Disconnect.
4. Select Yes on the message, which removes your business details and the Assign Income Tax categories and Submit quarterly update options in Nominal codes.

This removes the MTD options from Nominal codes and MTD for Income tax Settings from the Connected services menu.

If you need to reconnect, you'll need to set up MTD for Income Tax again.