Retrieve the holdings for an account

Example response

{
  "data": [
    {
      "date": "2018-07-11",
      "items": [
        {
          "id": "ac9bd177-d01e-449c-9f29-d3656d2edc2e",
          "codes": [
            {
              "code": "GB00B39TQT96",
              "type": "ISIN"
            }
          ],
          "description": "Dynamic Bond Fund",
          "quantity": 100,
          "total": {
            "value": 123400,
            "currency": "GBP"
          },
          "unitPrice": {
            "value": 1234,
            "currency": "GBP"
          },
          "costBasis": 120050,
          "currency": "GBP"
        }
      ]
    }
  ]
}