Link to downloadable report for org usage

Link is sticky so that it is easy to spot even when
an org has many services.

app/main/views/organisations.py

@@ -156,10 +156,20 @@ def organisation_dashboard(org_id):
         **{
             f'total_{key}': sum(service[key] for service in services)
             for key in ('emails_sent', 'sms_cost', 'letter_cost')
-        }
+        },
+        download_link=url_for(
+            '.download_services_report_for_org',
+            org_id=org_id,
+        )
     )
 
 
+@main.route("/organisations/<uuid:org_id>", methods=['GET'])
+@user_has_permissions()
+def download_services_report_for_org(org_id):
+    pass
+
+
 @main.route("/organisations/<uuid:org_id>/trial-services", methods=['GET'])
 @user_is_platform_admin
 def organisation_trial_mode_services(org_id):

app/templates/views/organisations/organisation/index.html

@@ -112,4 +112,10 @@
     <div class="keyline-block govuk-!-margin-top-2"></div>
   {% endif %}
 
+  <div class="js-stick-at-bottom-when-scrolling">
+    <p class="bottom-gutter">
+      <a href="{{ download_link }}" download="download" class="govuk-link govuk-link--no-visited-state govuk-!-font-weight-bold">Download this report</a>
+    </p>
+  </div>
+
 {% endblock %}

tests/app/main/views/organisations/test_organisations.py

@@ -624,6 +624,36 @@ def test_organisation_services_hides_search_bar_for_7_or_fewer_services(
     assert not page.select_one('.live-search')
 
 
+def test_organisation_services_links_to_downloadable_report(
+    client_request,
+    mock_get_organisation,
+    mocker,
+    active_user_with_permissions,
+    fake_uuid,
+):
+    mocker.patch(
+        'app.organisations_client.get_services_and_usage',
+        return_value={"services": [
+            {
+                'service_id': SERVICE_ONE_ID,
+                'service_name': 'Service 1',
+                'chargeable_billable_sms': 250122,
+                'emails_sent': 13000,
+                'free_sms_limit': 250000,
+                'letter_cost': 30.50,
+                'sms_billable_units': 122,
+                'sms_cost': 1.93,
+                'sms_remainder': None
+            },
+        ] * 2}
+    )
+    client_request.login(active_user_with_permissions)
+    page = client_request.get('.organisation_dashboard', org_id=ORGANISATION_ID)
+
+    link_to_report = page.find('a', text="Download this report")
+    assert link_to_report.attrs["href"] == url_for('.download_services_report_for_org', org_id=ORGANISATION_ID)
+
+
 def test_organisation_trial_mode_services_shows_all_non_live_services(
     client_request,
     platform_admin_user,