Not related but found imigration for a Maddern family that may be yours.
Richard (31), Phillipa (25), Solomon (3), Phillipa (2) and Elizabeth (infant) travelled to Victoria aboard Agincourt, arriving in March 1860 (unassisted). Phillipa died aged 4 in 1862. They had a further 11 chn (Ballarat/Beechworth/Eldorado). Phillipa snr's maiden name was WELLINGTON.
There were several other Maddern families arriving around this time, including Rose MADDERN with several children; a James MADDERN; John MADDERN and wife; and William & Phillis MADDERN (aged 41 & 39 respectively in 1849) with many children, ranging from infancy to age 20! The latter family is the one referred to in the original post here. Not sure if any connection as well.
Richard's death notice and obituaries (NLA Trove):
The Argus, Saturday 11 July 1914
MADDERN -On the 2nd July, at his late residence "Brooklyn" Byawatha, Wangaratta, Richard Trembath, the dearly loved husband of the late Phillipa Maddern, aged 87 years.
Wangaratta Chronicle, Saturday 4 July 1914
Death of Old Byawatha Identity.
The death occurred at mid-day on Thursday of Mr. Richard Trembath Maddern, of Byawatha, who was one of the oldest identities of that locality. Mr. Maddern, who resided at "Brooklyn" with his son, Mr Philip Maddern, had reached the advanced age of 81 years. For some considerable time he has been ailing and three weeks ago had to take to his bed, Dr. Docker was called in and Miss Wolls's services as nurse secured, but despite the careful attention bestowed he gradually sank. Death was due to senile debility. The late Mr. Maddern was a native of Cornwall, England, where he was brought up on a farm, receiving a good grounding in the working of a farm. He was married at Home, and with Mrs Maddern and three children came to Australia in the early fifties. Soon after their arrival two of the children died. Mr. Maddern was not long in the country when he found his way to the Woolshed goldfields, where he remained for some years working as a miner, but he did not meet with any great measure of success. While at the Woolshed his thoughts frequently turned to the land, and he selected an area at Byawatha, where with his wife and family he went to reside thirty five years ago. General farming and dairying were there carried on with success. Mr. Maddern was of a reserved nature, and did not enter into public life in any way. He was a good neighbour, and his upright actions won for him the esteem and respect of a large circle of acquaintances. His wife predeceased him seven years ago, and he leaves a family of seven sons and six daughters, namely, Mrs D. Scott, Mount Brophy, N.S.W.; Mrs C. Donaldson, Mt. Lyall, Tasmania; Mrs F. Mavay, Sydney; Messrs Solomon Maddern, Leongatha; Walter Maddern, Orbost; Richard W, Maddern, Mount Bishoff, Tasmania; William Maddern, W.A.; Phillip Maddern, Byawatha; Nathaniel H. Maddern, Sydney; Thomas H. T. Maddern, Melbourne. Mr. Wm. Maddern, of Chiltern, is a brother. The remains were interned in the Wangaratta cemetery yesterday, the funeral arrangements were carried out by Mr. T. Laidler. The burial service was road by Roe, Mr. Verris. The coffin bearers were Messrs V. Sheppard, Q. Luckle, J. Connor and J. Bullied.
Ovens and Murray Avdertiser, Wednesday 8 July 1914
DEATH OF AN OLD RESIDENT OF ELDORADO.-Another of the few remaining links between the present and the past in regard to the settlement of Eldorado district passed away at noon on Thursday in the person of Mr. Richard Trembath Maddern, who died at the residence of his son, Mr. Phillip Maddern, "Brook lyn," after a long illness. The deceased reached the advanced age of 87 years on June 19 last, and for the past six years he had been gradually failing. Three weeks ago he became seriously ill, and he was well cared for by his son and Nurse M'Waters, but he continued to fail until death ensued. Dr. Boyes attended him in his last illness. The deceased was born in Cornwall, England, and spent his early years mining and farming. Attracted by the gold discoveries in Victoria he decided to emigrate with his wife and child, and he arrived in time for the rush to Woolshed, where his wife's uncles (Messrs. Wellington) were already working. Mr. Maddern followed mining at the Woolshed, and afterwards further down the creek at Eldorado until the mines ceased, and he then secured a farm at Byawatha, where he remained until his death. When his declining health caused him to abandon work deceased's son carried on the farm, but the parents remained at their old home, and it was there that both of them passed their last days, Mrs. Maddern's death taking place about seven years ago. The late Mr. Maddern was a typical native of Cornwall, staunch in his friendship, industrious and good living, and a fine example of the men who laid the foundations of the settlement in the district. Of a quiet, unostentatiousnature, and devoted to home life, he took no active part in public affairs, but he was always regarded as an upright, honorable man, who was worthy of the highest respect, and has left a large family, whose members have become valuable and respected members of the community as the result of their early training. The deceased is survived by his sons, Messrs. Solomon and Walter (Gippsland), Richard (Tasmania), William (West Australia), Phillip (Byawatha), Nathaniel (Sydney), Thomas (Melbourne), Mrs. Scott (Cumellico, N.S.W.), Mrs. Donaldson (Tasmania), Mrs. Mavay (Sydney). The remains of the worthy old colonist were interred in the Wangaratta Cometery on Friday afternoon.
William John MADDERN died in Chiltern in 1915 aged 78, son of Solomon (reg 8516). Richard's brother?