Sorry Stewart there is a Charles Grant b 1883 Bristol in the 1891 census but his father is Thomas and Thomas was born Somerset

...No sign of a John of about the right age in the 1891 census Im afraid either
As to looking for a John of about the right age in 1871 there is only a 2 year old or a 16 year old visible....there is not one apparent of about 7 or 8 years of age ....again sorry
In 1881 same thing the two nearest in age r the 2 I found in 71...The elder one is now married to Jenny with 2 daughters
Kris