Update description text

Re: IATI#248 - make this clearer that this is managed / sourced by org-id

xml/OrganisationRegistrationAgency.xml

@@ -5,11 +5,13 @@
         </name>
         <description>
             <narrative>
-                The values from this codelist are used to identify the particular list that an organisation identifier was drawn from. The codelist provides a list of known identifier lists, including national company registers, NGO lists and international and multilateral lists - along with links to sources where specific organisation numbers and identifiers can be looked up.
+The values from this codelist are used to identify the particular list that an organisation identifier was drawn from. The codelist provides a register of known identifier lists, including national company registers, NGO directories and international and multilateral organisation lists - along with guidance and online resources to help locate the identifiers assigned to a specific organisation. 
 
-                As of 17 July 2017 the Organisation Registration Agency codelist (now organisation identifier list) is maintained centrally by org-id.guide. Open data publishers can now locate organisation identifiers using this website. IATI replicates the list directly from org-id.guide with the exception of the XI-IATI codelist. IATI still maintains the XI-IATI organisation identifier list, which is used  when there are no other available lists that might be used to provide a stable organisation identifier.
+As of 17 July 2017 this list is maintained by the org-id.guide project. Data publishers can now search for and locate the relevant list for a particular organisation identifier using the <a href="http://org-id.guide/">org-id.guide website</a>. The full register of identifier sources is also available to download in <a href="http://org-id.guide/download.xml">XML</a>, <a href="http://org-id.guide/download.json">JSON</a> and <a href="http://org-id.guide/download.csv">CSV</a> formats. 
 
-                If an organisation identifier list that you wish to use cannot be found in org-id.guide, you can submit a direct request on Github (https://github.com/org-id/register/issues) or email [email protected]
+IATI periodically replicates the codelist of identifier sources from org-id.guide, to assist those accessing IATI documentation.  However, it is advised that the most up-to-date source is the <a href="http://org-id.guide/">org-id.guide project</a>.
+
+If org-id.guide does not contain an entry for the kind of organisation you need to identify, you can make a request a new list is included in the register following the <a href="http://docs.org-id.guide/en/latest/contribute/">guidance or by getting in touch with <a href="mailto:[email protected]">[email protected]</a>.
             </narrative>
         </description>
     </metadata>