long shot this as I cannot identify all the stencilling. I acquired a canvas satchel a few yrs ago together with a couple of the wartime knapsacks used as panniers, I wanted these for my '49 MAC, I have just had an inquisitive look at the satchel and its shoulder strap, on the satchel is the stencil XX & SL 191? [X being indecipherable] the strap AL CO 1918, the bag is 11"x 9"x 2" deep, I'm quite made up really seeing how old it is and 'tis in use again to carry my bits and bobs.
can anyone further this perhaps?
kind regards

MW & SL is Martin Wright and Sons Ltd.

thank you, that's just cracking, they are still in business kind regards