Hey Tup as possibly the worlds leading expert of Club Mill Road: do you know what the "Cottages to the Old Park Silver Rolling Mills" were?
From Picture Sheffield
https://www.picturesheffield.com/frontend.php?keywords=Ref_No_increment;EQUALS;t12367&pos=40&action=zoom&id=143111
https://www.picturesheffield.com/frontend.php?keywords=Ref_No_increment;EQUALS;s28693&pos=12&action=zoom&id=89840
https://www.picturesheffield.com/frontend.php?keywords=Ref_No_increment;EQUALS;t12368&pos=3&action=zoom&id=143112
Based on these pictures I would say the remaining ruins are the cottages, except having had a snoop around the ruins don't look the same at all in terms of windows, roofline and arches.
The Britain From Above archives
https://britainfromabove.org.uk/sites/all/libraries/aerofilms-images/public/580w/EAW/040/EAW040042.jpg
https://britainfromabove.org.uk/sites/all/libraries/aerofilms-images/public/580w/EAW/040/EAW040044.jpg
https://britainfromabove.org.uk/sites/all/libraries/aerofilms-images/public/580w/EAW/040/EAW040045.jpg
Don't show anything else that looks like it could be the cottages though.