The real time plasma control system for the MAST Upgrade tokamak has been substantially redeveloped from its original MAST incarnation with a new architecture that aims to manage complexity whilst maximising flexibility. It provides modular layers of functionality and supports the implementation of virtual actuators to aggregate, arbitrate and route requests from multiple upstream controller functions to finite downstream actuator commands. Initial experience of this design and its exploitation during the commissioning and initial operation of MAST Upgrade to first plasmas is reported. We present here the current hardware and software architecture of the control system, highlighting how the layered architecture enabled the gradual commissioning of new functionality in step with the commissioning of the plant and the tokamak system, and later paved the way to allow new functionality such as position, shape and divertor strike point control to be added with minimal impact on already commissioned critical functions. Finally, we show how the next steps of the development roadmap for MAST-U plasma control will support more advanced capabilities in future scenarios.