Hi Richard!
Thank you for your inquiry, it has led me to find a lovely new source.
I will direct you to this link: https://data2.collectionscanada.gc.ca/080027/amicus-13325197.pdf
It is a publication from the Niagara Historical Society from 1910. Stamford Presbyterian Cemetery begins on page 51 of the book (page 53 of the PDF). John is discussed three pages later.
The transcription reads: ''John Chisholm, emigrated to Canada in 1779, born 1746, died 1830." The author also notes "This must have been one of the earliest of the United Empire Loyalists to come to this country.''