Yes, most likely the Mayor(ess) wanting to get his/her photo taken. I met the Mayor of Liverpool at a function many years ago. Prising out one of the 365 largish diamonds which, with other gems, adorned his chain of office would have enabled him to pay off the considerable amount he owed his Council in local taxes.
The big cheeses in some learned and professional bodies, old trade guilds and livery companies sport chains of office


, but I don't think Model Engineering Clubs show off like that.
Or maybe the local Freemasons were visiting
Andy