Baggage Delay's
The baggage loads at the moment are about 25% heavier than they would normally be at this time of year because of the current security rules. This is obviously having a major impact on the time it takes to load and unload aircraft.
Because the aircraft would have been picking up delays throughout the day due to this and the fact that STNs runway is presently closing at midnight on Sat & Sun for resurfacing, means that a large number of aircraft are landing between 23:30 and 00:00.
Also Swissport's late shift is rostered to finish at 23:59, leaving only a small amount of nightshift and any agents willing to stop on for overtime (bearing in mind that most of them would have started at 13:30 and will be fairly shattered because of the heavy loads they are coping with) to unload the late arriving aircraft.
As you can imagine all of this coupled together means that it will take longer to get your bags if you're coming into STN at around midnight on the weekend.
I know this wont make you feel any better about having to wait over an hour for your baggage but hopefully it will explain the reasons why.