Hi Maureen,
You wrote this a long time ago, in fact before I knew I was a Thackray. My great grandmother Mary Thackray was Horatio's sister, born in 1847. She maried Henry Barnsley in 1873 and had two children George 1874 and Tom 1876. She died in 1877.
I was interested in tracking down Mary's siblings, so I am delighted to find out more about Horatio.