Measure the double cream into a large bowl and whisk to soft peaks, then stir in the yoghurt. Halve the passion fruit, scoop out the pulp and add to the cream with the passion fruit purée. Add the banana slices and broken meringues and gently fold together. Divide the mixture between six 150-200ml glasses, shaping the top of the mixture into a peak with your spoon. Chill in the fridge until ready to serve. Shortly before serving, slice the meringues into shards and insert into the top of each glass. Garnish with a couple of passion fruit wedges, a drizzle of the passion fruit purée and a sprig of mint.
Note: if you’re not keen on banana you can replace it with 100g seedless white grapes, cut in half or a similar quantity of chopped mango.