A bit of info from the book Dream Palaces of Birmingham by Chris and Rosemary Clegg.
The Oak was originally opened in 1929 and redesigned by Harold Seymour Scott. The reconstruction work was carried out by T Elvins and Sons Ltd. The auditorium seating being increased from 1,093 tp 1,506. Reopening took place on the 16th Dec 1935 with George White's 1935 Scandals and The Flame Within. It became an ABC house and in common with other ABC cinemas in the 1960's was simply called the ABC. In April 1978 it was leased to Michael and Diane Flook,who kept it running back in it's original name of The Oak until the 3rd Nov 1979 when it closed with Quadrophenia and King Henry Roberts.