Overlap 2 (45cm long) sheets of cling film at their centers, forming a cross. Use the cling film to line the long and short sides of the loaf pan, letting the excess plastic wrap hang over the sides.
2) Scoop the softened vanilla ice cream into the loaf tin and smooth into a level layer using the back of a metal spoon. Sprinkle with 1/3 of the chopped espresso beans and return to the freezer until firm, about 15 to 20 minutes.
3) Remove from the freezer and smooth a layer of coffee ice cream on top of the vanilla ice cream and espresso beans. Sprinkle with an additional one third of the espresso beans and return to the freezer until firm, about 15 to 20 minutes.
4) Remove from the freezer and smooth a layer of chocolate ice cream over the layer of coffee ice cream and espresso beans. Fold over the excess cling film to enclose the terrine and return to the freezer until very firm, at least 1 hour.
5) To serve, remove the terrine from the freezer and unmold onto a chilled platter, peeling away and discarding the plastic wrap. Cut into slices using a knife dipped into warm water and wiped clean after each slice. Serve on cold plates garnished with the remaining chocolate-covered espresso beans.