Albert P Dunsmore did not emigrate to Canada at the same time as his family. In the 1881 census he was in Devon with John Isaac Parker and his wife Elizabeth. The census record indicates that he was John's grandson.
It took me a while to work out how this could be possible but I think the story goes like this:
1. Elizabeth Palfrey was born about 1836 in Dunster, Somerset daughter of William Palfrey, farmer.
2. In the March quarter of 1854 she married Thomas Townsend, son of Henry, a farmer. Registered at Williton, Somerset.
3. Clara Ellen Townsend was baptised on 18 Aug 1854 to Thomas Townsend, Timbescombe (near Dunster), miller and Elizabeth his wife.
4. I don't know what became of Thomas, but Elizabeth Townsend married John Isaac Parker in the March quarter of 1871. Registered in London.
5. Clara Ellen Townsend married James Dunsmore in Devon in June quarter of 1875.
6. Albert Peter Parker Dunmore was born in Devon in the June quarter of 1876, mother Townsend.
7. John Parker died in 1882, after which I can find no further record in England of Elizabeth or Albert.
So there is little doubt that Elizabeth Palfrey/Townsend/Parker was Albert's grandmother but could John Parker have been his grandfather, as stated in the census? Maybe. Albert was clearly conceived before Thomas and Elizabeth married and it is just possible that John Parker was already on the scene. A good use for a DNA test, especially if Albert has male-line descendants.