Slice fennel, onion and chorizo and place in an oven proof dish.
Place octopus leg on top drizzle olive oil and then pour in beer, season with salt and pepper.
Mix with hands so that everything gets mixed in and well coated - octopus should sit in the liquid.
Make a small cross with a sharp knife in the bottom of each cherry tomato and scatter around dish and then cover the dish and marinate for a couple of hours.
Pre heat oven to about fan forced 150.
Cover dish tightly with foil and prick once to allow for steam to escape.