I reproduced what you see with the TRTH SOAP API, using SoapUI. Your syntax is correct.

There are 2 reasons why you did not get any results:

1. There is no data available for the particular instrument you chose (VOD.L).
2. The restricted date range.

Below is a successful call for a different instrument (CARR.PA) and a wider date range (if you restrict the date range to what you originally used then you will not get any data either).

Hope this helps !

Request body:

   <soapenv:Body>
      <typ:GetRICSymbology>
         <typ:instrument>
            <typ:code>CARR.PA</typ:code>
         </typ:instrument>
         <typ:dateRange>
            <typ:start>2000-01-01</typ:start>
            <typ:end>2016-07-31</typ:end>
         </typ:dateRange>
      </typ:GetRICSymbology>
   </soapenv:Body>

Response body:

  <soapenv:Body>
      <GetRICSymbologyResponse xmlns="http://types.webservice.tickhistory.thomsonreuters.com">
         <instrumentList>
            <instrument>
               <code>CARRn.PA</code>
               <dateRange>
                  <start>2001-01-09</start>
                  <end>2003-05-08</end>
               </dateRange>
               <name>
                  <string>CARREFOUR NV</string>
                  <string>**SEE <CARR.PA>*</string>
               </name>
               <status>Verified</status>
               <statusInfo/>
               <exchange>
                  <string>NXT</string>
                  <string>PAR</string>
               </exchange>
               <type>
                  <string>113</string>
                  <string>225</string>
               </type>
               <currency>
                  <string>EUR</string>
               </currency>
               <peCode>
                  <string>6520</string>
               </peCode>
               <releaseCycle>0</releaseCycle>
            </instrument>
            <instrument>
               <code>CARR.PA</code>
               <isin>
                  <string>FR0000120172</string>
               </isin>
               <sedol>
                  <string>5641567</string>
               </sedol>
               <gics>
                  <int>30101040</int>
               </gics>
               <dateRange>
                  <start>1996-01-01</start>
                  <end>2016-08-15</end>
               </dateRange>
               <name>
                  <string>CARREFOUR</string>
               </name>
               <status>Verified</status>
               <statusInfo/>
               <exchange>
                  <string>PAR</string>
                  <string>NXT</string>
                  <string>PAR</string>
               </exchange>
               <type>
                  <string>113</string>
               </type>
               <expiryDate>
                  <dt>2007-03-09</dt>
                  <dt>2007-03-16</dt>
                  <dt>2007-03-19</dt>
                  <dt>2007-03-23</dt>
                  <dt>2007-03-30</dt>
               </expiryDate>
               <maturityDate>
                  <dt>2007-03-09</dt>
                  <dt>2007-03-16</dt>
                  <dt>2007-03-19</dt>
                  <dt>2007-03-23</dt>
                  <dt>2007-03-30</dt>
               </maturityDate>
               <currency>
                  <string>EUR</string>
               </currency>
               <peCode>
                  <string>3032</string>
                  <string>6520</string>
               </peCode>
               <underlyingRIC>
                  <string>CARR.PA</string>
               </underlyingRIC>
               <releaseCycle>2</releaseCycle>
            </instrument>
         </instrumentList>
      </GetRICSymbologyResponse>
   </soapenv:Body>