In the 1850s Fennell and his wife Maria, the eldest daughter of Melbourne pioneer John Batman, lived and farmed at Yarra Grange, a riverside property in what is now Abbotsford. While Fennell’s primary business was a shipping agency, at Yarra Grange the couple produced fruit and vegetable crops, and ran dairy cows. Several of their children were born on the property. 

Although the property had belonged to James Simpson in the 1840s, it became associated from 1850 with various relations of John Batman, of whom Simpson had been a friend and executor. Batman’s widow Eliza and her second husband, William Willoughby, lived at Yarra Grange around 1850-51. The botanist Daniel Bunce, who studied and published on Australian flora and indigenous culture, had some involvement with plantings at Yarra Grange.  In 1851 he married another one of the Batman daughters, Pelonamena, and was perhaps living at Yarra Grange prior to moving to Geelong.

Fennell was active among local residents of note. In 1853 he presided over a meeting to discuss the parlous state of Simpsons Road (Victoria Street). A motion was passed to collect subscriptions and then apply to the Country Roads Board for a grant. Others at the meeting included Peter Nettleton and Jesse Fairchild. In 1855 Fennell was on the committee of the Collingwood Bridge Company, formed as a joint-stock company to raise capital for a bridge, eventually sited at the end of Church Street.

Maria took an active part in managing the business matters of the farm while her husband was occupied in his city office. In 1854 she advertised for ‘an English couple, the man as Gardener and the woman as Cook, must thoroughly understand their business.’ She had lost her first husband while still in her teens, and herself died very young on 13 April 1856.

Fennell packed up almost immediately and went home to Ireland with his children. Yarra Grange – 25 acres and dwelling house - was advertised for sale from 18 April 1856:

The land is in a state of high cultivation, and there is not a waste rood in the whole. The orchard, which is the oldest in the colony, cannot be excelled in its fruit trees, which comprises a large portion of the estate; the residue is divided into two paddocks, and has always been managed as a market garden and dairy farm.

By 3 May Fennell was ready to sell off his goods and chattels. As well as household furniture there were farming implements, about 20 tons of fine hay, nine cows (of which five were in full milk) a quiet bay horse, and a dog-cart amongst other itemised equipment.In July the property was sold to Eardley Blois Norton for £5000. Fennell lived the rest of his life in Ireland.