I realize that I could construct a passable office chair using 3D sectors, but as I intend to use such a chair many times in my project it makes most sense to use a model.
Nigel, I looked through the pix of models that you sent me, and all I saw was a bench. It's a nice-looking bench, but it just doesn't cut it in an office setting.

Any chance that you could whip up a simple model of an office chair, preferably the swivelling kind - I mean the chair is meant to swivel not the model.