Wanted: Medium/small crate/cage for car

Preferrably plastic (Vari Kennel, Atlas etc.), but steel is ok as long as they're not foldable (those are a death trap to dogs in cars!).

My dog is about the size of a Fox Terrier/Parson Russel, 35cm high. We can pick it up in a pretty wide range around Oxford, as we are travelling quite a lot.