Thanks for your help.
I have tried this - not ideal as its really structured as something where people see/share each other's contributions. In this case the tabs confuse people, suggesting there is something more to do than simply upload your file. I'm still mystified as to why Moodle puts in all the grading information on an assignment even when you select grading as "none".
It is actually an assignment - its just I don't want to the confusion and clutter of grades and they don't really apply in this case.
Very frustrating trying to do something as simple as get a student to upload file without any extra clutter.