Hi Lynda,
Welcome to RootsChat

Looking at theses births from the GRO site,
BirthsJoseph John DOVEN Dec Q 1890 Saint Olave Southwark 1d 225
mmn: DEERING
Charles Walter DOVEN Jun Q 1892 Saint Olave Southwark 1d 226
mmn: DURING
Keturah DOVEN Mar Q 1895 Camberwell 1d 1014
mmn: DEARING
Margaret DOVEN Sep Q 1896 Camberwell 1d 993
mmn: DEARING
and these baptisms,
Christ Church, Bermondsey, Southwark
05 May 1891
Joseph John
Parents: Joseph John Francis & Margaret DOVAN
11 L??y Road
Boot maker
St Mary Magdalene, Bermondsey, Southwark
Charles Walter
19 Jan 1894
Parents: Joseph John Francis & Margaret DOVEN
61 St??worth St
Boot Maker
St Bartholomew, Camberwell, Southwark (Keturah and Margaret on the same day)
04 Sept 1896
Born: December 25th 1894
Keturah
Parents: Joseph John Francis & Margaret DOVEN
86 Credon Rd
Boot Maker
Born: August 15th 1896
Margaret
Parents: Joseph John Francis & Margaret DOVEN
86 Credon Rd
Boot Maker
The 25th December 1894 DOB for Keturah would make her 6 for the census taken on 31 March 1901.
I think Keturah and Katherine are the same person and that the enumerator could have misread the name when he copied the original form into the enumerators book.
Regards,
Daisy