Looks like the family went to Western Australia:
The West Australian, Monday 31 July 1944
LATTIMORE.--On July 29, 1944, at Kalgoorlie, Elizabeth, widow of the late Frank Lattimore; beloved mother of Frank, May, Stanley and Roy; mother-in-law of Martin and Eileen and grandmother of Joy and Tom; aged 80 years. Peace.
She is interred at Boulder Cemetery.
Roy died in Perth, WA in 1951 (reg 2973). There were lots of notices for him, but here are the family's ones:
The West Australian, Wednesday 21 November 1951
LATTIMORE (Roy Norman): On Nov. 19, at Mount Hospital, passed away, suddenly, dearly loved husband of Eileen, brother of May (Mrs. Berg). Wonderful pal.
LATTIMORE (R. N.): On Nov. 19 suddenly, at Mount Hospital, beloved brother and brother-in-law of May and Martin Berg (Subiaco-road), uncle of Tom and Joy (Mrs. Hunt). Deeply grieving.
His wife Eileen died 24/7/1952. It appears they had no children.
May's first husband's WWII enlistment (he was a clerk, married with one child, deemed medically unfit and did not serve):
MOULE Walter Leith : Service Number - V74393 : Place of Birth - Ascot Vale VIC : Place of Enlistment - South Melbourne VIC : Next of Kin - (Wife) MOULE May
May B MOULE remarried in Perth in 1951 to Martin H BERG (reg 1793). They are buried at Collie Cemetery:
BERG , Martin Henry. 5 Sep 1971 aged 78. Husband of May. Anglican N.50
BERG , May Beatrice. 6 Jun 1966 aged 79. Wife of Martin, mother of Tom and Joy. Anglican N.50
I think Joy was Walter & May's daughter; she married Percival F HUNT in 1936 in the goldfields under both surnames (Berg & Moule). Martin's son Tom (Thomas Bruce) also married, to Joan NEAL in 1950. He died aged only 47 in 1975. Joan may still be living but may have remarried. His WWII enlistment:
BERG THOMAS BRUCE : Service Number - WX23133 : Date of birth - 22 Dec 1926 : Place of birth - MELBOURNE VIC : Place of enlistment - KARRAKATTA WA : Next of Kin - BERG MARTIN
Possible death for Frank snr in WA in 1908 in Northam district (reg 51), which fits with the will in Victoria in 1909.
Sadly, still a dead end for son Stanley. Elizabeth's death certificate would tell you if he was still alive when she died.