CSV Report now works

Finished the CSV report download

Signed-off-by: Kieran Briggs <kieran.briggs@sheffcol.ac.uk>
Changed to download only in csv file format

Now only allows you to download as a csv file (work is still included for xls and ods for later date.

Signed-off-by: Kieran Briggs <kieran.briggs@sheffcol.ac.uk>