I have a snippet of info which may be of interest to you.
My mother Ida Alderson was born to Mary Ann Alderson in Askrigg, Wensleydale in 1912. Mary Ann was born to Sarah Alderson in 1893. Mary Ann and Sarah worked in domestic service and their children were illegitimate - hence the Alderson name surving down the female line. I have always been told that it would be very difficult to trace any ancestory on my mother's side, but you never know - the name Alderson must have come from somewhere. I know nothing more of Sarah, but I would expect she was born circa 1863 to 1875. It's just possible her name appears on the fringes of your tree somewhere.
PS Sorry if this appears more than once - having difficulty getting it to post