Getting start form fields

Hello,

We have defined a form as follows

<bpmn:startEvent id="StartEvent_1">
  <bpmn:extensionElements>
    <camunda:formData businessKey="workflowId">
      <camunda:formField id="workflowId" label="Work Flow Id" type="string" defaultValue="${uuidService.generateUuid()}">
        <camunda:validation>
          <camunda:constraint name="readonly" />
        </camunda:validation>
      </camunda:formField>
      <camunda:formField id="A_Base" label="The base asset on which the payment will be made" type="string" />
    </camunda:formData>
  </bpmn:extensionElements>
  <bpmn:outgoing>SequenceFlow_0lh09k4</bpmn:outgoing>
</bpmn:startEvent>

When we make the request to get the form variables we just get the following with out any of the extra information like the workflowId will be set to the businessKey and is read only

localhost:8080/rest/engine/default/process-definition/key/simple_flow/tenant-id/37/form-variables

{
  "A_Base": {
    "type": "String",
    "value": null,
    "valueInfo": {}
  },
  "workflowId": {
    "type": "String",
    "value": "1b2038a7-fe8b-4758-9dd0-01cdeebd0947",
    "valueInfo": {}
  }
}

Is there a way of getting this information without retrieving the generated form and parsing that?

Thanks,
Matt