@Darragh Martin, Thanks for posting in Q&A. For retire action, it removes managed app data, settings, and email profiles that were assigned by using Intune. The device is removed from Intune management. It will not remove any personal data. After the device is retired, you can use local account to login the device. Here is a link list the information which will be removed on windows devices when doing retire:
https://learn.microsoft.com/en-us/mem/intune/remote-actions/devices-wipe#windows
Hope the above information can help.
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