[5] Around 1850 Gillies' studio was at 36 Percy Street, where she briefly gave a home to the "auto-icon" of Jeremy Bentham,[6] on whose cadaver Southwood Smith had conducted a highly controversial public dissection in 1832.

[7] She went in 1851 to Paris for a year, where she worked in the studios of Hendrik and Ary Scheffer, and on her return to England she exhibited some portraits in oils.

[6] The 1861 census records Mary Gillies 60, authoress and Margaret Gillies 56, Artist in Water Colours, living at Heath House, Weybridge with Thomas S Smith, 72, physician and widower, his son Herman Smith 40, Wine merchant, his granddaughter Gertrude Hill 23, lady, and also a cook and servant.

[2] After Smith's death, Margaret and Mary Gillies lived for many years at 25 Church Row, Hampstead, and worshipped at the Unitarian Chapel, Rosslyn Hill.

In 1866 Margaret bought a grave plot in the dissenters' section of the western side of Highgate Cemetery for a stillborn baby of Charles and Gertrude Lewes.

Mary was later interred in this grave on 23 July 1870, as was Catherine, the widow of the poet and critic Richard Hengist Horne, on 6 September 1893.

[1] Her portrait of Charles Dickens, painted during the period when he was writing A Christmas Carol, was in the Royal Academy of Arts' 1844 summer exhibition.

[15] After viewing it there, Elizabeth Barrett Browning said that it showed Dickens with "the dust and mud of humanity about him, notwithstanding those eagle eyes".

The painting's location was unknown (from later in Gillies' lifetime, when she was unable to trace it) until it was rediscovered in Pietermaritzburg, South Africa,[15][16] and acquired and restored by the art dealer Philip Mould in 2018.