Power and control isolation is necessary for many applications including isolated gate drive supply, device characterisation and the testing of power electronics converters. Commonly the isolation stage is integrated directly into the converter and therefore cannot easily be repurposed for another project, serviced in case of failure or easily adjusted for other power supply requirements. This paper proposes a modular, flexible, isolation stage that can easily be connected to the prototype under test, has a variety of power supply options, digital channel flexibility and can be easily replaced in case of failure. The load regulation of the module outputs have been experimentally measured and are presented. The proposed isolation stage has been utilised for the control and gate drive supply isolation in a 1MHz switching frequency Capacitor-Inductor-Inductor-Capacitor (CLLC) Resonant Dual Active Bridge (RDAB) converter to demonstrate the isolation stages usefulness in high switching frequency applications.