Complex sentence: After a time at the Pavilion Theatre, the orchestra moved back to the "new" Winter Gardens with an inaugural concert on 18 October 1947 and continued to give many concerts there until the mid 1980s when the Poole Arts Centre became its main venue.
Split into simpler sentences: After a time at the Pavilion Theatre, the orchestra moved back to the'new' Winter Gardens with an inaugural concert on 18 October 1947. The orchestra performed regularly there until the mid 1980s, when the Poole Arts Centre became its main venue.