Welcome to Apple Support Communities, Pete!
If you're not getting any notifications for your Apple applications or 3rd party apps, have a look at this article: Use Notifications on your iPhone, iPad, and iPod touch -- Especially read the information under the heading "If you don't see notifications for a specific app".
Here are some troubleshooting steps to use if you haven't tried them already. They're listed from easiest to hardest. Test your notifications after each step before moving to the next.
1. Restart your iPhone Restart your iPhone, iPad, or iPod touch
2. Reset Network settings If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network -- This will only affect previously connected Wi-Fi networks and passwords, recently used Bluetooth accessories, VPN and APN settings.
3. Still not receiving Notifications, then you'll Use iTunes on your Mac or PC to restore your iPhone, iPad, or iPod to factory settings
Be sure not to neglect backing up your iPhone since erasing your device through iTunes removes even the operating system, failure to back up your phone will result in data loss. How to back up your devices using iCloud or iTunes
This time through the restore process, set up your iOS device as new and don't restore your back up just yet. You may need to download some of the applications you mentioned to test the notification feature of your iPhone. If the issue is resolved, go ahead and restore your device from your back up -- Restore your device from an iCloud or iTunes backup
Take care!