diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 446e4f86..5dcadaa2 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -35,7 +35,7 @@ jobs:
     services:
       rdf4j:
         # Docker Hub image
-        image: eclipse/rdf4j-workbench:4.3.15
+        image: eclipse/rdf4j-workbench:5.1.0
         ports:
           - 8080:8080
 
diff --git a/src/cimsparql/sparql/bus.sparql b/src/cimsparql/sparql/bus.sparql
index 9556294f..6deff47c 100644
--- a/src/cimsparql/sparql/bus.sparql
+++ b/src/cimsparql/sparql/bus.sparql
@@ -33,17 +33,15 @@ where {
     }
   } .
   optional {
-    # When an EIC code does not exist, look for an EIC code in neighbouring nodes
-    filter(!bound(?direct_bidzone))
-    {
-      select ?top_node (max(?connected_bidzone) as ?nearby_bidzone) {
-        ?con_node cim:ConnectivityNode.TopologicalNode ?top_node .
-        ?_eq_subj2 <http://entsoe.eu/CIM/EquipmentCore/3/1> ?eq_repo2 .
-        service ?eq_repo2 {
-          # Collect bidzones from substations connected to the current substation via a ConductingEquipment
-          ?con_node ^cim:Terminal.ConnectivityNode/cim:Terminal.ConductingEquipment/^cim:Terminal.ConductingEquipment/cim:Terminal.ConnectivityNode/cim:ConnectivityNode.ConnectivityNodeContainer/cim:VoltageLevel.Substation/SN:Substation.MarketDeliveryPoint/SN:MarketDeliveryPoint.BiddingArea/entsoeSecretariat:IdentifiedObject.energyIdentCodeEIC ?connected_bidzone .
-        }} group by ?top_node}
+    select ?top_node (max(?connected_bidzone) as ?nearby_bidzone) {
+      ?con_node cim:ConnectivityNode.TopologicalNode ?top_node .
+      ?_eq_subj2 <http://entsoe.eu/CIM/EquipmentCore/3/1> ?eq_repo2 .
+      service ?eq_repo2 {
+        # Collect bidzones from substations connected to the current substation via a ConductingEquipment
+        ?con_node ^cim:Terminal.ConnectivityNode/cim:Terminal.ConductingEquipment/^cim:Terminal.ConductingEquipment/cim:Terminal.ConnectivityNode/cim:ConnectivityNode.ConnectivityNodeContainer/cim:VoltageLevel.Substation/SN:Substation.MarketDeliveryPoint/SN:MarketDeliveryPoint.BiddingArea/entsoeSecretariat:IdentifiedObject.energyIdentCodeEIC ?connected_bidzone .
+      }} group by ?top_node
   }
+
   bind(coalesce(?direct_bidzone, ?nearby_bidzone) as ?bidzone)
 
   FILTER regex(?area, '${region}')