The Woodstock PR Transcript shows that William and Mary married on this date, but the marriage is listed under the Banns section which indicates that they married elsewhere. It states that Mary was from Ketteringham, Norfolk so it maybe that they married there.

WOODSTOCK Banns
1902 Jun 1 KNIBBS William James otp br. BREWSTER Mary Ketteringham (Norfolk) sp

We understand from an interview given by William's son, William John Knibbs in Feb 1993, that William became very ill and was sent home from hospital in Oxford to die, but by following the advice of the vet he recovered, and worked for another 13 years.
__________

We see William and his family in 1911 living at Woodstock, Oxfordshire:
KNIBBS WILLIAM JAMES M 1873 38
KNIBBS MARY F 1873 38
KNIBBS WILLIAM JOHN M 1903 8
KNIBBS HILDA MARY F 1905 6

It's understood from Trevor Knibbs that Mary was born and died at Woodstock, Oxfordshire, England.

However, looking at BREWSTER in Ketteringham, Norfolk in 1901(which is where Mary was reported to be living at the time of the banns) there was just one BREWSTER family consisting of George (54), his wife Ann (53) and a son Henry (33).
Ann Brewster 53 Berkshire Wokingham Norfolk Ketteringham
George Brewster 54 Norfolk Shelthorpe Norfolk Ketteringham Gamekeeper Head
Henry Brewster 33 Berkshire Warefield Norfolk Ketteringham Under Gamekeeper

This same family appeared in the 1881 census living at Warfield Park, Warfield, Berkshire. So I believe that Mary was in fact born at Warfield in Berkshire, and not Woodstock.

George BREWSTER Head M Male 32 Felthorpe, Norfolk, England Gamekeeper To Lord Ormathwade
Ann BREWSTER Wife M Female 31 Wokingham, Berkshire, England
Henry George BREWSTER Son Male 13 Warfield, Berkshire, England Scholar
William James BREWSTER Son Male 11 Warfield, Berkshire, England Scholar
Mary BREWSTER Dau Female 8 Warfield, Berkshire, England Scholar
John BREWSTER Son Male 6 Warfield, Berkshire, England Scholar
Charles ENGLEFIELD Keeper U Male 28 Wokingham, Berkshire, England Gamekeeper

(Note: the above was the property of Lord Ormathwaite)

So, how did Mary meet and eventually marry William Knibbs? The 1901 census shows that she was working as a domestic in Woodstock which is where William's family originated.
(Mary Brewster 29 Berks Bracknell Oxon Woodstock Housemaid Domestic)