The photo posted by Matt, 23 April, shows the interior of the church of Our Lady Immaculate, about 1960. It was built in the 1830s, designed by J.J. Scholes, a prolific architect of catholic churches in the mid nineteenth -century. The church was restored and refurnished in 1960, followed by more changes after the reforms of the Second Vatican Council in the 1960s (the Council affected the liturgy and furnishings of catholic churches throughout the world).
In 1996, Bangor's catholic community moved to the old Anglican church of St James in Upper Bangor, which was renamed the church of Our Lady and St James. The old church in High Street became the Black Bull pub (Weatherspoons) and retains the arcades and some other features of the original building.
For more details of the history, see the well researched booklet, The Catholic Community in Bangor 1827-2007, by Roberta Canning.