Preheat the oven to 200C/400F/Gas 6. Chop or slice all of the vegetables into roughly equally sized pieces and set aside.
For the crumble, put the gluten free flour into a mixing bowl. Chop the lactose free butter into little lumps and add it to the gluten free flour.
Using your fingers rub the gluten free flour and lactose free butter together. Keep going until it looks like breadcrumbs. Stir in the oats, cheese, pepper and seeds. Set aside.
Meanwhile, heat a large saucepan and melt the lactose free butter until it bubbles slightly. Add the garlic infused oil and stir for a minute.
Add the gluten free flour and stir well for another minute. The lactose free butter and gluten free flour will thicken and change colour slightly.
Gradually add the stock or lactose free milk a little at a time, stirring as you pour. The sauce should thicken up and not be lumpy.
If it is you will need to mix it really fast to get rid of any lumps. Taste your sauce. You may want to add some salt and pepper, grated cheese or just a squeeze of lemon juice.
Add the chopped fresh vegetables to the sauce and cook gently for five minutes, stirring often.
Pour the saucy vegetables into a 20cm/8in square baking dish and let it cool slightly. Sprinkle the crumble all over the top of the vegetables.
You should cover all of them up and have a nice thick crumble topping.
Place the dish onto a baking tray (to catch any spills) and bake in the oven for 30-40 minutes or until the crumble is golden-brown all over. Remove the crumble from the oven and leave to cool slightly before serving.