Thanks again for looking this stuff up.
I have a newspaper cutting already, attached here, but sadly it mentions no date. It mentions Major Deare, who I checked was Major from 1876 to 1888, and there are nominal rolls for the regiment at Kew, which I haven't seen yet, though I go there from time to time as it's only an hour away.
Also attaching his marriage clipping, though again no year, and neither say which paper.
These were both saved by my grandfather's brother, who told his daughter all about his boyhood and family on Jersey, though if John Thomas left in the 1870's they couldn't have known each other. His daughter, who is my cousin and is still alive, kindly copied these for me some years ago.
Graham