Heat oven to 220C/fan 200C/gas 7. Put a pan of water on to boil, then cook the gluten free lasagne sheets for about 5 mins until softened, but not cooked through. Rinse in cold water, then drizzle with a little oil to stop them sticking together.
Meanwhile, heat the oil in a large frying pan, then fry the zucchini until it has softened and turned bright green, add in the spinach and allow to quickly wilt.
Stir in 2/3 of both the lactose free cream cheese and the cheddar, then season to taste. Heat the passata in the microwave for 2 mins on High until hot.
In a large baking dish, layer up the lasagne, starting with half the zucchini mix, then gluten free pasta, then tomato sauce.
Repeat, top with blobs of the remaining lactose free cream cheese, then scatter with the rest of the cheddar.
Bake on the top shelf for about 10 mins until the gluten free pasta is tender and the lactose free cheese is golden.