I started by looking at the 1881 census. He was already living in Clifton then as his parents had a lodging house there. His father Henry was from Warminster in Wiltshire, whereas his mother Eliza was shown as a local lass, being born in Clifton herself. The family had two domestic servants and George had a younger brother Arthur.
He was shown as a Commercial Traveller in the Wine Industry, so it's possible that he worked his way up from that.
If I were you, I would try to find him in the full run of Censuses returns from 1861 onwards to get a feeling for the family's fortunes. You could also look to see when his father died and see if there was a will, which would be another way of getting a feeling for the family's social situation.
Kind regards
Philip Candy