Based on the signatures, we’ve pinned this down to sometime between 1920 and 1922.
Burnley topped Division One in 1920/21, then finished third the following season.
Can any Burnley fans identify exactly which season this comes from?
UPDATE: Thanks to Ralph Pomeroy for getting in touch, spotting that Bob Chambers was at Lincoln until 1922. He made four appearances for Burnley in the 1922/23 season – so that confirms the date (and that we we’re a year or two out!)