Hi Teaema
On the 1861 cnesus his mother is shown as Hannah, born c1802, Durham Hylton, widowed.
William is listed as William STEWARD Henderson, aged 20. Its possible that the Steward comes from his mother's maiden name.
The IGI has a couple of *possibilities* for baptisms:
William Henderson baptised 9 Aug 1840, West Rainton, Durham, father Ralph, mother Ann
William Henderson baptised 30 November 1840, Gateshead, father Samuel, mother Ann.
hope this helps
PAul