S. Isabel Dacre’s Portrait of Lydia Becker, previously dated c.1885-c.1890, can be arguably dated to 1885, having being exhibited at the ‘Manchester Academy’ in February 1886 (The Manchester Weekly Times, 27 Feb 1886).
Oil paint, especially dark colours, takes weeks or even months to ‘dry,’ after which a varnish is often applied which also takes some time to fix. Technically oil paint does not ‘dry,’ it oxidises and hardens. This allows artists to finely hone their works before the image became fixed. Even then, oil solvent can be applied and areas reworked.

This all assumes the newspaper is referring to the same painting now held by Manchester Art Gallery. The article gives the work great praise, commenting on the delicate tones and general emotional quality, not just being a technically good both otherwise uninvolving portrait.
Jonathan Russell