The company were not clock makers, nor so far as I know, makers of anything, but clocks, especially clocks of a commercial nature, are often signed Gensign.
The company was actually called "General Signal and Time Systems Co Ltd." and they bought in equipment from other makers to assemble their systems.
It appears that they did a large volume of business with their suppliers as most if not all of the items have been signed Gensign in place of the manufacturers badge.
An example is the British railway system which used large numbers of digital display units badged gensign but made by Solari of Italy. Clocks made by EZ (Elektrozeit) and badged Gensign are known, also clocks by Magneta (the British company controlled by BVC)
The Gensign badge in a Magneta clock in my possession gives their address as 73 Gt. Peter Street London SW1.
I have a copy of a brochure showing a wide range of equipment which they supplied.
Included are:
Master clocks, slave clocks and programme wheels
Time recorders and Job costers
Wall clocks
Staff Location systems and Light Signals
Individual radio, Broadcast paging systems and "Music While you work" installations
If you would like a zip file of this brochure please email me and while you are at it, tell me all YOU know about Gensign, history of the company and who actually made the clocks and other items they used.