Hi Stuart,
Thanks for your post. Generally speaking, In Date & time, you can choose to let Windows 10 set your time and time zone automatically, or you can set them manually.
To set your time and time zone in Windows 10, go to Start > Settings > Time & language > Date & time.
Also, please make sure the region is also set in Control Panel >Region >Administrative > current location.
Best Regards,
Ian Xue
If the Answer is helpful, please click "Accept Answer" and upvote it.