Came across some fun illustrations
here (on page 40), but the history starts only in 1861 and there is no mention of Henderson. Disregarding the sales announcements of this token, I did find several mentions of a James Henderson, architect in the 1920s. A more significant find was "Henderson Travel", which apparently had a fleet and service routes in Lanarkshire and Monklands until 2014, according to
Wikipedia. See also
this document with 187 mentions of Henderson travel with address 4, Whistleberry Park, Hamilton ML3 0ED, an industrialised area, some hits connected with Monklands Hospital.
The token looks more modern than 1850/60's. The decorations do not look modern, though. The word omnibus does not apply only to horse-drawn multi-passenger vehicles, but also to the first bus lines replacing electric trams, much later. However, INSIDE suggests that there were outside seats (an important distinction in the Scottish climate) also.
I believe Breingan is still around, but can he be contacted?
Peter