Apparently this place was formerly part of Fagins (Rafters) night club. Olivers Pub Bar was open during the day and was a large drinking den with Youngers Scotch bitter, keg Tartan, a "quiet oasis..." and an additional saloon-style bar offering drinkers "compartments with a privacy rarely found in pubs today" . Rafters was thriving throughout the the '70s so it sounds like this place was entirely separate from the club.
1. The Manchester Pub Guide, Manchester & Salford City Centres (1975).