Thank you Helen and Ann for that information and the extraordinary photos of 120 Much Park Street. It has filled in quite a few gaps in my research.
I will do my best to respond to both your posts collectively, and in doing so may also provide some information to other forum members and visitors about the James Muir family and their connection to Coventry.
The James Muir cited in the 1921 Census and residing at 17 Chapel Street is my granduncle. He was born 13th June 1870 on Beoch Farm outside Maybole in Ayrshire to James Muir (1843-1921) and Helen Muir nee McNab (1844-1929). On 17th January 1888 James (a Fishmonger aged 18) and Margaret Ellen McCutchion (a Spinster aged 19) were married in The Church of St David in Birmingham.
That same year, they moved to Coventry where they had six children, all born in Coventry: Margaret Helen Muir (1888-1955), James William Muir (1889-1971), Edith Evelyn Muir (1891-1894), Harold David Muir (1898-1925), Evelyn Victoria Muir (1901-1956), and Reginald Gilbert Muir (1904-1968).
After the death of his wife Margaret in April 1907, James remarried in November 1917 to Lizzie Bailey nee Tomkins (1890-1964).
James died on 1st December 1947 at 50 Foleshill Road in Coventry.
[Photos of James and Margaret]

The James William Muir cited in the 1921 Census and residing at 123 Colchester Street is the son of James and Margaret E. McCutchion. He was born on 6 December 1889 in Coventry. James William Muir married Sarah Ellen Hughes (188-1954) in Coventry. They had three children, all born in Coventry: James Walter Muir (1914-1999), Marjorie Helen Muir (1918-2006) [she married Henry Eric Charley 1914-1975], and Derek Muir (1928-1988).
In 2018, my wife and I visited Coventry and met up with our cousins, the two daughters of Derek Muir, Lesley French (Muir) and Lynda Bradford (Muir), and Michael Charley the son of Marjorie Helen Muir.
I look forward to reading many of the other stories on Coventry, as sadly, my wife and I had but a very brief visit of two days and did not get the opportunity to see all that Coventry had to offer by way of its history and heritage. Perhaps, on the next visit.