1. Put 250 ml (8 fl oz) water in a saucepan.
2. Add 100 g (4 oz) of the sugar and heat gently, stirring, until the sugar has dissolved.
3. Set aside 15 ml (1 tbsp) lemon juice in a cup. Add the rest of the lemon juice to the saucepan with the orange juice.
4. Dissolve 20 ml (4 tsp) of the gelatine in a little of the hot liquid in a small bowl. Cool, then stir into the remaining liquid in the saucepan.
5. Rinse a 750 ml (1 1/4 pint) mould and line with some of the jelly. Chill for 10 - 20 minutes until set.
6. Slice a banana thinly and arrange overlapping slices in a design on the set jelly. Cut the angelica into leaf shapes and arrange over the bananas.
7. Carefully spoon over just enough of the remaining jelly to cover the decoration. Chill again. When all the jelly in the mould is set, add enough extra jelly to give a total depth of about 10 cm (4 inches).
8. Mash the remaining 4 bananas or process briefly in a blender or food processor. Pour the banana puree into a measuring jug and make up to 250 ml (8 fl oz) with milk.
9. In a bowl, whip the cream to soft peaks; fold in the banana mixture.
10. Put 60 ml//4 tbsp water in a small heatproof bowl. Sprinkle the remaining gelatine on to the liquid.
11. Stand the bowl over a saucepan of hot water and stir the gelatine until it has dissolved completely.
12. Remove from the heat and stir in the remaining sugar, with the reserved lemon juice. Set aside.
13. When the gelatine mixture is cool, but not set, stir it into the banana cream.
14. Pour into the prepared mould and chill until set.
15. Turn out on to a wetted serving plate.