Recollections on the Edinburgh Photographic Society website indicate Dunbar & Co was a separate company, based at Edinburgh's Pleasance. Dunbar & Co was possibly taken over by James Dunbar.
Stone bottles
The trade mark is a man on horseback with the motto 'second to none'. The smaller bottle (003) is much simpler with no trademark.
Glass bottles
These glass bottles are similar in design although 005 (right) is larger.
004 is date stamped on its bottom as 1912 whereas 005 is 1924. Both have 'D' and 'C' interlocking.
The bottle tops are different and may not be with their original bottles.
004 shows 'Dunbar & Co' with the interlocking 'D' and 'C' and 'Edinburgh'.