Hi izzie, It must have been a very good year for magnolia this year, I've seen many trees/ shrubs set seed this season.
If you remove the pods by holding them between your thumb and fore finger and give it a wee twist as you pull it should stop the tree putting all its energy into seed production and hopefully give you a greater number of bloom's next year. In other words 'dead head' them as you do with Rhododendrons. Good luck Tbird+