Apple rhubarb custard tart

Name: Apple, rhubarb & custard tart
Ingredients: 375g pack dessert pastry; 250g rhubarb cut into small pieces; 300g eating apple peeled, cored and cut into small pieces; 2 tbsp caster sugar; juice 1 orange; 150ml double cream; 150ml milk; 1 vanilla pod halved; 3 eggs; 85g caster sugar; zest 1 orange