How do I call create permissions on Google Drive API via Delphi

I'm trying to use Delphi to call Google Drive Permissions API to create a permission on a team drive. All goes well with the setting on the Google Try It section, but my Delphi code isn't working.

reqPermissions.Body.Add('{role: "organizer",type: "user",emailAddress: "it_admin@mycompany.com"}');

I've tried supplying the type field as a parameter in the Request component, but this also doesn't work. Driving me nuts at the mo, so any help much appreciated.

I always get the following response:

{
  "error": {
    "errors": [
      {
        "domain": "global",
        "reason": "required",
        "message": "The permission type field is required.",
        "locationType": "other",
        "location": "permission.type"
      }
    ],
    "code": 400,
    "message": "The permission type field is required."
  }
}