I have been redeployed as part of the COVID-19 response from my managerial position into a hands-on clinical role but at a lower pay level. Do I keep my substantive wage?   

In short, yes. If your employer has directed you to be redeployed as part of this workforce response, then the terms of your employment contract, along with your award or agreement, would continue to apply. Some awards or agreements have provisions for managing redeployments and ancillary issues if the redeployment requires you to relocate to another place of work. Take care as well, to ensure that the new role is within your scope of practice and that the required PPE is available.