Put sherry and passionfruit pulp into a shallow dish. Dip biscuits, one at a time, in the mixture and arrange over the base and partially up the side of a large glass bowl. Reserve the passionfruit syrup.
Arrange the sliced mango on the biscuits, making sure the fruit is showing around the sides of the bowl.
To make the custard, put the cream and vanilla bean in a large saucepan and slowly heat until almost boiling. Whisk together the egg yolks, sugar and cornflour, then gradually whisk in the cream. Return the custard to the saucepan and cook, stirring continuously until the custard thickens (do not boil). Cover the surface with plastic wrap and allow to cool.
Pour the custard over the mangoes and top with the whipped cream. Cover and refrigerate overnight.
Serve the trifle topped with crumbled meringue and the reserved passionfruit pulp.