The insignia that appears in The Great London Conspiracy is largely built of tropes that appear in conspiracy media and lunatic fringe, along with the more common pieces of crest and heraldic art in Victorian England.
As with much of the book, it was feverishly researched and assembled upon trends of the time period, to create a symbol that was ominous, sinister but - most importantly - realistic; something similar to the Freemasons that could have been seen in the City of London at the time.
The spoked wheel was, originally, a wagon wheel in most crests and designs of the period; but the ongoing industrialisation of England and advance of technology resulted in many companies and families adopting the railway wheel in their artwork - a symbol of technology, speed and fortitude. As railway companies adopted this new twist on traditional heraldric artwork, many family names and organisations followed suit. If your town has an Industrial Cooperative building, you'll no doubt see many references to the locomotive.
The eye is probably the most well-known aspect of crest and logo design in the world, thanks to the cultural knowledge of the Illuminati and other 'New World Order' phenomena. The eye is a symbol directly relating to governmental charge and providence, relating it directly with control and intelligence - the concept of the 'All Seeing Eye' has been referenced in popular media so much it's difficult not to recognise it.
The original designs of the crest involved a clenched fist in the eye's place - a common piece for military heraldry or the image of control.
The wings are that of a vulture - a bird affiliated with evil, death and greed for centuries. Heraldic sources refer to the Vulture as a 'gripe'. Most crests of the period would choose a more elegant form of a bird of prey rather than a scavenger - the vulture was a decision taken from the way the organisation operations - picking and stealing from numerous sites and, of course, the Eternal Tome.