If anyone is interested, a colleague put me onto a good browser based tool for playing with the new Stingray REST API (HT to Rick Nelson). It is available from http://restconsole.com (links to the Google Chrome Web Store) and you might also need the plugin that puts a button in your browser to launch it called "REST Console Launcher"
The RESTClient works pretty well for those of us using Firefox
Although I had to manually add a customer header to set the correct Content-Type. Under Headers, click "Custom Header" and then create a "Content-Type" header with the value set to "application/json". You don't need it for browsing the API, but you will if you want to make any changes.
1. RESTclient does not accept IP addresses, it needs to be the full hostname:9070 (or whichever port)
2. Also make sure that you have already accessed the Stingray console via Firefox and accepted the security certificate before using the REST client, because RESTclient does not report security errors directly