David from the support team helped me work this issue out. It turns out that I was missing the web.config update required for REST requests to work properly.
docs.kentico.com/display/K82/Configuring+the+REST+service#ConfiguringtheRESTservice-ConfiguringtheRESTservice
- Edit your application's web.config file.
- Find the system.webServer section directly under the root (i.e. not under a specific