Looks like two of Robert Theodore & Elizabeth Hughes children married Guttormsen's. And they did have another son Robert Bruce. See Robert Bruce's engagement notice , Thomas Theodore's marriage and also Elizabeth Hughes death notice, which connects the families and children.
The Courier-Mail (Brisbane, Qld. : 1933 - 1954)(about)issue Tuesday 2 August 1949
HUGHES- GUTTORMSEN.— The engagement is announced of Valmai, second Daughter of Mrs. M. and the late Mr. A. Guttormsen, Cannon Hill. Brisbane, to Robert Bruce, second Son of Mr. and Mrs. R. T. Hughes. Widgee Gympie.
The Courier-Mail (Brisbane, Qld. : 1933 - 1954)(about) Saturday 15 April 1950
HUGHES— GUTTORMSEN — Heather from Scotland will be included in the bridal bouquet of Miss Valmai Guttormsen (Cannon Hill), and she will; wear lace for her wedding to Mr. R. B. Hughes (Gympie) in the Cannon Hill Presbyterian Church. The honeymoon will be spent on the South Coast.
The Courier-Mail (Brisbane, Qld. : 1933 - 1954)(about) issue Wednesday 15 September 1954
HUGHES.— The Relatives and Friends of Mr. R. T. Hughes. Mr. and Mrs. T. T. Hughes. Mr. and Mrs. V. Guttormsen (Widgee) and Mr. and Mrs. R. B. Hughes, of Morningside and Families, are respectfully Invited to attend the Funeral of his beloved Wife, their Mother, Mother-ln-law. and Grand mother. Mrs. Elizabeth Hughes, to move from St. Peter's Church of England. Gympie. This (Wednesday, Forenoon, after service commencing at 10.45. to the Gympie Cemetery JACK CORNES Funeral Director Gympie
The Courier-Mail (Brisbane, Qld. : 1933 - 1954)(about) issue Friday 24 December 1943
HUGHES— HARDY.— On Dec. 4th. 1943, at St. Peter's Church of England. Gympie, by the Rev. J. Howard Steer. Thomas Theodore Hughes, eldest Son of Mr. & Mrs. R. T. Hughes. Widgee. Gympie. to Syvina Jane Hardy, eldest Daughter of Mr. H. J. Hardy & the late Mrs. Hardy, of Taree. N.S.W.