I checked all 3 Wallingford parishes (St Leonards, St Marys, St Peters) and there's no sign of either the marriage or Mary's baptism.
I made a note of what I did find for this family, in case you haven't already got it and it's of any use.
St Peters
Baptised 19 Mar 1837 Vincent BOSLEY s/o Vincent, lab & Mary Ann, St Peters Church Lane.
Bp Aug 25 1839 Priscilla BEISLEY d/o Vincent, lab & Mary Ann, St Peters Church Lane.
Bp Apr 26 1846 Joseph BEISLEY s/o Vincent, lab & Mary Ann, Brew House Lane.
St Marys
Bp 25 Jan 1842 George BEISLEY s/o Vincent, painter & Mary Ann, Castle St.
St Leonards
Buried Jul 24 1847 Vincent BEISLEY 46 years, Old Moor Lane.
Married Sep 29 1851 John Pratt x f.a. bach. otp lab. s/o Charles, lab & Mary Ann BEISLEY x f.a. widow otp d/o William Kent (no further details of father) Witnesses: Henry Moody, Richard Child.
So, if you didn't know before, it looks like Vincent married a Mary Ann Kent - just got to find it now!!
Jill
Logged
See Surname Interests Table + Major brickwalls: John Frith mge to Fanny, Bucks? c 1798 Bathsheba Boothroyd bp W Yks c1802 John Bishop bp E Yks c1758 Joseph Symonds mg to Sarah, prob Berks c 1735-40 John Horwood mg to Martha, Berks c 1735-40 Sarah Sculler bp Berks area c 1675 Paul Phillips bp Berks/Bucks c 1720 William Newell bp Berks/Bucks/Oxon c 1765 Richard Troughton mg to Jane, Westmoreland c 1732 Mary Simon bp Shrops c.1795