Hi Joe,
I think it is the same John Edwards in those censuses, with the 1871 one a mistranscription of the first "4" for his age: "44". Judging by the others (given in my previous message), and comparison with Cath's age, it should read 34.
In 1861 he was aged 25, 1881 aged 45, 1891 aged 53, 1901 aged 60. Even though these are inconsistent, as they usually are, Cath's age is 3-5 years younger, except for that one year 1771 when she is 13 years younger.
The other John Edwards 33 chimney sweep in 1901 was their son, who was with them aged 24 in 1891.
Sue