The Monument has been attributed to Henry Cheere.
James Cooper d.1745.
His wife had predeceased him by many years and the head of her statue is probably idealised.
The squarish nose on the head of his wife looks very similar to that of the Hon. Elizabeth Maynard on the monument at Little Easton Essex of 1746 - that monument is by the Dane Stanley who was working in England from 1718 - 1746 when he returned to Denmark.
The figures on the monument are perhaps by Louis Francois Roubiliac.
This is dangerous territory for me and I might be doing Henry Cheere a huge disservice but I fail to be convinced that Henry Cheere was responsible for sculpting much of the sculpture given to him in particular the portrait busts. That is not to say that he didn't design or superintend their manufacture in his workshops at Old Palace Yard, and Millbank, Westminster.
It was made at about the same time as the Cheere Monument to the 13th Earl of Kildare at Christchurch, Dublin - This remarkable, innovative and most theatrical monument was completed by 6 September 1746 when reported in London Evening Post - 'on Wednesday last the Right Honourable Earl of Kildare viewed the fine and curious monument made by Mr Cheere an eminent statuary, in Westminster to the memory of his father'. See -
https://bathartandarchitecture.blogspot.com/2016/10/monument-to-13th-earl-of-kildare.html
The Cooper Monument is inscribed -
James Cooper... who... Desired that under his EFFIGIE after his Name and Age to be Written this (or to this Purpose): I Believed // In one God, Father, Son and Holy Ghost, // Also the Resurrection // And whilst I liv d, I Firmly put my trust // In his Divine protection. // But now interrr d, I m cover d or e [over] with Dust, // Reader prepare, for there unto you must.