His estate was worth about £3m when he died. He had two heirs, his daughters Elizabeth and Margaret Lauretta, who both married improvident aristocrats: Elizabeth married
Lord Edward Thynne in 1830, and Margaret married
The 2nd Earl of Glengall in 1834. The same year Margaret paid for a family vault for her father in
Highgate Cemetery. In 1847, Elizabeth unsuccessfully attempted to gain a greater share of their father's estate with a court case. The trustees of the estate also felt concern over the profligacy of Lord Glengall, an
Anglo-Irish nobleman, who went bankrupt in 1849 during the
Great Famine in
Ireland, a status he retained until his death in 1858. The trustees were able to sell much of the family estates in Ireland in 1853 through the
Encumbered Estates' Court, with much of the land being subsequently bought back. He was originally buried in Wapping, with his father Peter Mellish, his mother and brother, all of whom were removed and interred in the family vault in
Highgate Cemetery when the Wapping Church was closed. ==References==