Combine the cheeses and herbs in a small bowl. To assemble the lasagne, spread one-fifth of the sauce in the bottom of a round 28cm baking dish (or a 30cm x 20cm rectangular dish), then top with a fifth of the cheese mixture, followed by a layer of lasagne sheets, broken to fit where necessary. Repeat these layers three more times in that order, and finish with a final layer of sauce and cheese: that’s five layers of sauce and cheese and four layers of pasta.