I want to make a clay sculpture. It is a box with a special shape that
I made up, and is not buyable. Nothing special in that, because there
are an infinite amount of possibilities anyone can make a new shape.

But I don't have a kiln and don't know anyone with one!

I live in London, England. How would I go about this, with spending
the least amount of money? Where would I go to get some baking done?
Anyone have some advice??