Hidden Glasgow history

So who were the Burtons - James Arnold and Barbara Jessie - who laid these foundation stones in 1929 on Dumbarton Road, Glasgow?
Thousands upon thousands of shoppers must pass by here without ever noticing them.
A quick check on Google reveals they were members of the family which owned the Burtons gents outfitters. Barbara Jessie was the daughter of shop founder Sir Montague Burton.
Not only that, there are similar stones in other cities including Cork, Taunton, Brighton, Mansfield and Aldershot.