@Chris Hunt: Sadly, when you swipe a notification away via the drop down notification panel, this will remove the icon badge for the associated app. I suppose the logic behind this is that the phone thinks you have read the notification, or you no longer need to be notified when you swipe it away, so the reminder isn't needed on the app icon itself. All I can suggest is leaving your notifications in place in the drop down panel until you open the relevant app, so the icon badge stays put. You might also wish to try enabling notification reminders to see if this restores the badge: Settings > Notifications > Advanced Settings > Notification Reminders > On.
