From what I can see Frederick Henry Clark married a Doris Stephenson Mar.qtr.1930 Orsett but she must have been either a widow or divorced. Her surname appears to have been mistranscribed sometimes on childrens births:
Doris Beetson b.25/12/1902 (birth reg'd Mar.1903 Prestwich, Lancashire, d.1969 Thurrock) married a William J. Stephenson Jun.1919 Prestwich and at least 1 son Ronald born 6/5/1924 Prestwich, d.1990 Thurrock. By 1930 Doris and her son are in Essex where she marries Frederick Henry Clark - children found:
Frederick A G b.19/11/1930, d.1986 - mmn Beatson
Colin b.1932, d.2002 - mmn Beetson
Alan Gary born 28/12/1933, d.1976 - mmn Beetson
Possible dau. (probably still living) born 1937 - mmn Bettson
Annette