Hi Anthony

On the 1881 census I can see the following:

Elizabeth LEWIS Head W Female 59 St Briavels, Gloucester, Eng.
William LEWIS Son U Male 34 West Dean, Gloucester, Eng. Engine Driver
Wm. George LEWIS Gd Son U Male 15 West Dean, Gloucester, Eng. Iron Miner

Dwelling Clements End
Census Place West Dean, Gloucester, England

This makes it look as if Elizabeth Lewis is Grandmother to William George Lewis. Isn't clear as to whether the other William could be Williams's father though. Clements End isn't very far from Bream.

There was a William George Lewis c. 7 Sep 1865 St. James, Bream, Gloucestershire, Eng. to a mother Eliza Lewis on the IGI. This I think is likely to be your man, shame it doesn't show a father. If I find anymore I'll let you know.

Joanne.

Here he is in 1871:

Clements Tump, West Dean.

Betsy Lewis Head W. 49 b. St. Briavels, Glos.
William Lewis Son 24 Engine Driver at Iron Mine b. West Dean, Glos.
George Lewis Son 22 Iron Miner b. West Dean, Glos.
Thos Lewis Son 19 Iron Miner b. West Dean, Glos.
William Lewis G. Son 5 Not at School, b. West Dean, Glos.

and Elizabeth/Betsy in 1861:

Clements End Green, West Dean

Elizabeth Lewis Head Widow 40 b. St. Briavels, Glos.
Eliza Lewis Daur. 16 b. Parkend, West Dean, Glos.
William Lewis Son 13 b. West Dean, Glos.
George Lewis Son 12 b. West Dean, Glos.
Cornelius Son 9 b. West Dean, Glos.

Eliza Lewis aged 16 in 1861 is more than likely your William George Lewis's mother.

Joanne.