Checked the 1881 cenus
1881 UK Cenus:
Robert Wall age 18, born Dublin
Living at 39 Union Street, at Victular(drink) William Bough
he is a postman, Marlebone Civil Parish, All Souls
other residents are Bar Man, Frank godden age 21 Bar Inn Hotel
Robert was a Potman
POTMAN was a merchant peddling pots of stout and porter. Porter is a type of beer which is dark coloured. The name came about in the 18th century due to the drink's popularity in London among river porters.