I've done a bit of trawling through the naval records available on various family history websites and have only found one record that completely fits, i.e. two first names beginning with J and A. If you only look for J obviously the numbers become unmanageable.
The one that fits is John Allan Upton who served in the Merchant Navy and was eligible for the Mercantile Marine Medal. Attached is his medal card from the National Archives. Unfortunately it is rather sparse on details, such as no date of birth. It does, however, include an address at Parkbeg, Saskatchewan, Canada.
This sailor is pretty much certainly the same person as a John Allan Upton born in the third quarter of 1880 in Guisborough, North Yorkshire, who emigrated to Canada around 1906 and appears in the 1921 Canadian census at Parkbeg Village, Swift Current, Saskatchewan. He is living with his parents, wife and four children, the eldest of whom was born in England, the rest in Sask. He and his father are postmen; his mother is the postmistress. He is also the census enumerator for the district, so one can hopefully rely on the information given about his own family! I've found them in 1911 as well, although the page is almost illegible. He was a farmer then.
He is buried in
Mountain View Cemetery, Vancouver, and his dates are given as 17 July 1880 - 25 Jan 1962.
It's clearly not a given that your man with the tag is the same as this John Allan Upton, but there must be a reasonable chance.