Food containers (Tufnell Park N19)

Does anyone have any of these containers which are delivered to cafes and restaurants and, usually, get thrown out when empty. In the past I got some from a local cafe but they no longer have them, and I don't fancy traipsing around from place to place in search of them. They are almost cubed-shaped, 24 x 24cms (9½in) at the top, and come with a lid and handle.