pizza oven

Hi All, It's Pizza Oven Time!! The oven itself is pre-built 1m x 1m and 500kg. It will sit on a 3 sided (1m x 1m x 1m), double skin brick wall 1.2m high. Question is, what should the foundation look like? I'm thinking 1.2m 1.2m x 0.3m concrete slab on 50mm hardcore. The ground is quite soft...