Thankyou for your wonderful advise, I had no idea they were so highly prized, I am not sure what you would consider 'old' these are from the late 9o's as I bought them from a small bakery in Western Australia, they still had some flour in them which took many washes to remove!
On the bag is printed;
25kg Net
West Australian
FLOUR
First Grade
West Coast Milling
Canning Vale West Australia
H/624
The quality of the cotton is not unlike Cotton Duck but a little softer as I have washed them several times now. Gal