CON - - MILLS, LEEDS, 1, Seal, Image & Found by Lancastrian.
Found in the Yorks / Lancs border area.
A seal with LEEDS across the middle and words around the edge starting with CON(C?)--- and ending with -ILLS mills? A large number 1 is all that appears on the other side.
Possibly grade 1 flour.
See BSG.BS.02047 for another seal that identifies this one.