Best bet for the mother's maiden name is a birth certificate of one of the children.

The 1881 census shows a John (5) and a William (2) which would fit. They seem to have been living with Ellen Kinrade at 4, Quayles Court, Ramsey. They are listed as sons, but I suspect they may have been grand sons, Together with Edward (9).
Ellen is shown as married (55), no husband present. I have not investigated her as yet.
There is no sign of John & Margaret.
Maybe Margaret was a Kinrade.