The National Physical Laboratory (NPL) and the WISH instrument team has worked together to enable simultaneous real-time high resolution (powder and single crystal) neutron diffraction and electric polarization measurements as function of temperature and magnetic fields. We propose to use the commissioned system to measure the dynamic coupling between the crystallographic and the magnetic structure of the novel room temperature multiferroic Aurivillius compound as function of ac electric field and track the magnetoelectric coupling from room temperature down to base T. This experiment will be the first to fully exploit the new WISH-NPL capability and explore in real time the multiferroic structural properties as function of several external stimuli (Electric field, Frequency, Temperature) in a technologically relevant multiferroic system.