Mail appears twice in notification centre

Thanks for getting back to us with that information, Epsom salts. It's appreciated.

Restart your iPhone - Apple Support -- Let's see if restarting your iPhone halts the duplicate notifications. First, go to Settings > Notifications and turn off notifications for the Mail app. Then, restart your iPhone. Once it's back to the Home Screen, turn notifications back on for Mail and test.

Update your iPhone, iPad, or iPod touch - Apple Support -- If you're still getting duplicate notifications, please update your iPhone. The current iOS version is 15.1.

If the issue persists after updating, please contact Apple Support: Get Support

Thanks for using Apple Support Communities!

Hey Epsom salts,

It appears that you're seeing notifications for email on your iPhone twice in the Notification Center, and we're glad to provide assistance.

Change notification settings on iPhone - Apple Support -- Review the notifications settings of the Mail app on your iPhone to be sure it's set correctly. 

If they are, please provide the answer to the following questions: 

1. Is one of the notifications in a list of email and another in a Scheduled Summary? 
2. Is this only happening from the Home Screen or also on the Lock Screen?
3. Is this happening with every email or just a few?
4. What device is this happening with and the iOS version it’s currently on (Settings > General > About)?

All the best.