I believe you may be right.. hey may not have married.
Joseph died in 1951 aged 38 making his birth c 1913.. no birth found.. not Brown or Soutter or any given combination.
Harold the eldest son and Joseph the youngest..
This is a marriage entry for a Rose Hannah Brown to Mark Milne in that time frame.. as it happens... the Rose anna Brown that died when her clothing caught fire is the mother of this Rose Hannah Brown that married Mark Milne. coincidence ??