Mystery object answer
Last month’s mystery object (October 2017) was a donkey stone.
This was a new one on me and resulted in a bit of research:
According to Wikipedia (and other reliable sources) a donkey stone was ‘a type of scouring block, used mostly in the mill towns of the north of England to clean stone steps’ see en.wikipedia.org/wiki/Donkey_stone for more info.
Thank you to everyone who guessed. Mystery object for November on its way…