Thomas Inman was married to William's sister Jennet: (http://en.wikipedia.org/wiki/Thomas...)

<Daniel Newham (whose brother, William Leighton Newham, A.M., formerly fellow of S. John's college, Cambridge, is now vicar of Barrow-on-Soar, near Loighborough) was the eldest son of Mr. Daniel Newham, who had for some years a mill at Preston for spinning linen yarn. The son married, in 1843, Mary, daughter of J. Bluett, esq., advocate, Douglas, Isle of Man. He afterwards entered Emmanuel college, Cambridge, but did not graduate, going out with bishop Perry to Melbourne in 1847, where he became the first incumbent> (http://booksnow2.scholarsportal.inf...)

indicates that William''s father was spinner Daniel Newham at Preston. We find him in the 1841 census:

Daniel Newham 60 Flax Spinner born in Scotland
Jennet Newham 45 born in Lancashire England
Daniel Newham 20 born in Lancashire England
Jennet Newham 20 born in Scotland
Margaret Newham 20 born in Scotland
William Newham 15 born in Scotland

Note that William 15 should be born ca. 1826 (not 1823).

<Newham, William Leighton, born March 14th, 1823. Left Christmas, 1843. Son of D. Newham, Douglas, I.O.M. Cumming’s. Scholar, St. John’s College, Camb., 1844. Fellow 1847. 25th Wrangler.16th 1st Class Classics 1847. D. 1848. P 1849. V. of Barrow-upon-Soar, Leicestershire, 1854-1889. V. of Aldworth, Berks, 1889-1900. Retired. Nicosia, Cyprus.> (http://www.isle-of-man.com/manxnote...)

This shows that William was in King William's College, Isle of Man, for 1 year (1843). That college burn down on 14 Jan. 1844, which will explain why he continued at Cambridge. <D. Newham, Douglas, I.O.M> means Douglas in Isle of Man, where his father lived after Scotland but before Preston. <Nicosia, Cyprus> ?? This may explain why William can't be found in the 1901 census.

<Baptism: 11 Jun 1824 St John, Preston, Lancashire, England Leighton Newham - [Child] of Daniel Newham & Jennet>

Not William Leighton Newham but just "Leighton Newham", baptised in Preston 1824 even if born in Scotland 1823.

<1815--Daniel Newham, Esq. of Glasgow married J. Hyndman, niece of William Leighton, Esq. of Preston.> The Glasgow connection... apart from many other sources mentioning a Daniel Newham merchant company in Glasgow.