The research is very interesting so I have decided, with permission, to publish it here:
"I have been researching my tree for several years but couldn't find anything on my grandmother as there seemed to be two Mary's registered for that year but neither appeared on the 1881 census. I did find a Mary on the 1891 census living with the Hopkinson family at Mill House Farm, Hodsock, Nottinghamshire. This gave her place of birth as Little Gringley, Nottinghamshire.
I then sent for her marriage certificate and this gave her father's name as John Allen - gardener. One of the witnesses was Elizabeth Stockdale. I checked the 1891 census and found the Allen's neighbours were Benjamin and Elizabeth Stockdale. The 1901 census showed the Allen's living in Grove, Nottinghamshire and John as being a garden labourer. I already knew that she gave birth to a son just prior to her marriage, the place of birth being given as Grove, Nottinghamshire. I also discovered that Elizabeth Stockdale's maiden name was Allen but I think she was probably a cousin and not her sister.
Then I took a good look at the 1881 census again and I believe the name given as Sally is actually Polly and I am assured by several people that this was a common nickname for Mary. However this didn't solve the problem of the two Mary's so I sent for both birth certificates - one was the Mary above and the other was born to Elizabeth Allen of Moorgate, Clarborough, Nottinghamshire and no father's name given. This child was born in August 1871 and there is a recorded death of a Mary Allen in September 1871 (aged 0 years) so could be the same person.
My grandmother married George Bacon on October 29th 1894 at Ordsall Parish Church and lived the rest of her life in Everton where George was born and brought up." - Courtesy of the family of Mary Allen.
I am extremely grateful to this descendant of Mary ALLEN for sharing her research and hopefully other descendants of the ALLEN line may see these pages and make contact.