Process biscuits until mixture resembles fine breadcrumbs. Add butter, process until juist combined.
Using one hand, press crumb mixture evenly over base and side of 21cm springform tin. Cover, refrigerate 30 minutes or until firm.
Meanwhile, beat cheese, sugar and juice in small bowl with electric mixer until smooth and creamy; transfer to large bowl. Sprinkle gelatine over the water in small heathproof jug; stand jug in small saucepan of simmering water. Stir until gelatine dissolves; cool 5 minutes. Whip cream until soft peaks form, fold into cheese mixture; fold in gelatine mixture.
Drain cherries, reserve 180ml of the syrup for topping.
Spoon one third of cheesecake mixture into tin, top with half of the cherries, then continue layering, ending with cheese mixture, refrigerate 3 hours or overnight until set.
Spread topping over cheesecakes, swirl gently into cheese mixture. Refrigerate until set.
For the topping, blend cornflour and sugar with reserved cherry syrup in small saucepan. Stir over heat until mixture boils and thickens, stir in rum; cool 10 minutes before serving.