Line a 9 inch spring bottom round cake tin with nonstick paper. Make the jam by placing the berries, sugar and port into a saucepan and cook down together for 5 minutes. Take off the heat and let it cool down. Meanwhile, make the cheesecake base by mixing all the ingredients together and press into the base of the cake tin. Allow to set in the fridge while you prepare the filling. Place the cream cheese, sugars, treacle and spices into a large bowl and mix together till smooth. Soak the gelatin leaves in the orange juice and zest, then melt in the microwave. Carefully fold the whipped cream into the filling mixture, followed by the gelatin mixture. Spoon half of the port jam over the cheesecake base and spread out. Next, spoon in the filling and even out with a palette knife. Place in the fridge to set for at least 2 hours. To serve, remove from the tin and place onto a serving plate and decorate with the remaining jam, gingerbread and rosemary.