Why does RestSharp only parse the outer XML tag, not the inner data?

I have a server that sends back this xml:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<DataRequestResponse>
<Reports>
<ReportBlocks>
    <RowDates>2014-08-01</RowDates>
    <RowDates>2014-08-04</RowDates>
    <RowDates>2014-08-05</RowDates>
    <Values>3.79</Values>
    <Values>3.798</Values>
    <Values>3.79</Values>
</ReportBlocks>
</Reports>
</DataRequestResponse>

I made these C# classes:

public class DataRequestResponse{
    public List<Reports> Reports { get; set; }
}

public class Reports{
    public List<ReportBlocks> ReportBlocks { get; set; }
}

public class ReportBlocks{
    public List<string> RowDates { get; set; }
    public List<string> Values { get; set; }
}

Then I run the web service query with:

var client = new RestClient("https://example.com");
var request = new RestRequest ("the/api", Method.POST);
string query = "<q>whatever</q>";
request.AddParameter("application/xml", query, ParameterType.RequestBody);
var response = client.Execute<DataRequestResponse>(request);

response.Content is correct. However when I look at response.Data I have one entry in Reports but the ReportBlocks inside it is an empty list.

Where could I be going wrong?

I have RestSharp working nicely for another part of this API, which actually felt like the more complex XML, so I am a bit stumped why it is not working here.

(I have elided the attributes, and some other child XML elements, from the above XML example; but my other tests have shown that RestSharp happily ignores the attributes and nodes you are not interested in.)