Operators of flexible assets seeking to maximise value from their assets have numerous options for their trading strategy. Sources of revenue include trading energy on the wholesale market; providing balancing services to the National Energy System Operator (NESO); capitalising on opportunities created by imbalance pricing; and more recently providing Flexibility Services to the Distribution System Operators (DSOs). Each revenue stream comes with associated commercial and regulatory complexity, and almost all of them are subject to ongoing development. Flexibility Service providers need to ensure areas of complexity do not inhibit their ability to provide services into different markets and potentially stack revenue opportunities. In response, it is incumbent on the DSO market facilitators to ensure arrangements are developed that minimise any friction between markets and allow as much participation as possible.