diff --git a/rialto/runner/config_overrides.py b/rialto/runner/config_overrides.py
index 310c58e..72d59ac 100644
--- a/rialto/runner/config_overrides.py
+++ b/rialto/runner/config_overrides.py
@@ -1,33 +1,60 @@
-from typing import Dict
+#  Copyright 2022 ABSA Group Limited
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+__all__ = ["override_config"]
+
+from typing import Dict, List, Tuple
 
 from loguru import logger
 
 
+def _split_index_key(key: str) -> Tuple[str, str]:
+    name = key.split("[")[0]
+    index = key.split("[")[1].replace("]", "")
+    return name, index
+
+
+def _find_first_match(config: List, index: str) -> int:
+    index_key, index_value = index.split("=")
+    return next(i for i, x in enumerate(config) if x.get(index_key) == index_value)
+
+
 def _override(config, path, value) -> Dict:
     key = path[0]
     if "[" in key:
-        name = key.split("[")[0]
-        index = key.split("[")[1].replace("]", "")
+        name, index = _split_index_key(key)
+        if name not in config:
+            raise ValueError(f"Invalid key {name}")
         if "=" in index:
-            index_key, index_value = index.split("=")
-            position = next(i for i, x in enumerate(config[name]) if x.get(index_key) == index_value)
-            if len(path) == 1:
-                config[name][position] = value
-            else:
-                config[name][position] = _override(config[name][position], path[1:], value)
+            index = _find_first_match(config[name], index)
         else:
             index = int(index)
-            if index >= 0:
-                if len(path) == 1:
-                    config[name][index] = value
-                else:
-                    config[name][index] = _override(config[name][index], path[1:], value)
+        if index >= 0 and index < len(config[name]):
+            if len(path) == 1:
+                config[name][index] = value
             else:
-                if len(path) == 1:
-                    config[name].append(value)
-                else:
-                    raise ValueError(f"Invalid index {index} for key {name} in path {path}")
+                config[name][index] = _override(config[name][index], path[1:], value)
+        elif index == -1:
+            if len(path) == 1:
+                config[name].append(value)
+            else:
+                raise ValueError(f"Invalid index {index} for key {name} in path {path}")
+        else:
+            raise IndexError(f"Index {index} out of bounds for key {key}")
     else:
+        if key not in config:
+            raise ValueError(f"Invalid key {key}")
         if len(path) == 1:
             config[key] = value
         else:
@@ -38,8 +65,8 @@ def _override(config, path, value) -> Dict:
 def override_config(config: Dict, overrides: Dict) -> Dict:
     """Override config with user input
 
-    :param config: Config dictionary
-    :param overrides: Dictionary of overrides
+    :param config: config dictionary
+    :param overrides: dictionary of overrides
     :return: Overridden config
     """
     for path, value in overrides.items():
diff --git a/tests/runner/test_overrides.py b/tests/runner/test_overrides.py
index 0962c0e..996fa10 100644
--- a/tests/runner/test_overrides.py
+++ b/tests/runner/test_overrides.py
@@ -1,10 +1,25 @@
+#  Copyright 2022 ABSA Group Limited
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+import pytest
+
 from rialto.runner import Runner
 
 
 def test_overrides_simple(spark):
     runner = Runner(
         spark,
-        config_path="tests/runner/transformations/config.yaml",
+        config_path="tests/runner/overrider.yaml",
         run_date="2023-03-31",
         overrides={"runner.mail.to": ["x@b.c", "y@b.c", "z@b.c"]},
     )
@@ -14,7 +29,7 @@ def test_overrides_simple(spark):
 def test_overrides_array_index(spark):
     runner = Runner(
         spark,
-        config_path="tests/runner/transformations/config.yaml",
+        config_path="tests/runner/overrider.yaml",
         run_date="2023-03-31",
         overrides={"runner.mail.to[1]": "a@b.c"},
     )
@@ -24,7 +39,7 @@ def test_overrides_array_index(spark):
 def test_overrides_array_append(spark):
     runner = Runner(
         spark,
-        config_path="tests/runner/transformations/config.yaml",
+        config_path="tests/runner/overrider.yaml",
         run_date="2023-03-31",
         overrides={"runner.mail.to[-1]": "test"},
     )
@@ -34,8 +49,57 @@ def test_overrides_array_append(spark):
 def test_overrides_array_lookup(spark):
     runner = Runner(
         spark,
-        config_path="tests/runner/transformations/config.yaml",
+        config_path="tests/runner/overrider.yaml",
         run_date="2023-03-31",
         overrides={"pipelines[name=SimpleGroup].target.target_schema": "new_schema"},
     )
     assert runner.config.pipelines[0].target.target_schema == "new_schema"
+
+
+def test_overrides_combined(spark):
+    runner = Runner(
+        spark,
+        config_path="tests/runner/overrider.yaml",
+        run_date="2023-03-31",
+        overrides={
+            "runner.mail.to": ["x@b.c", "y@b.c", "z@b.c"],
+            "pipelines[name=SimpleGroup].target.target_schema": "new_schema",
+            "pipelines[name=SimpleGroup].schedule.info_date_shift[0].value": 1,
+        },
+    )
+    assert runner.config.runner.mail.to == ["x@b.c", "y@b.c", "z@b.c"]
+    assert runner.config.pipelines[0].target.target_schema == "new_schema"
+    assert runner.config.pipelines[0].schedule.info_date_shift[0].value == 1
+
+
+def test_index_out_of_range(spark):
+    with pytest.raises(IndexError) as error:
+        Runner(
+            spark,
+            config_path="tests/runner/overrider.yaml",
+            run_date="2023-03-31",
+            overrides={"runner.mail.to[8]": "test"},
+        )
+    assert error.value.args[0] == "Index 8 out of bounds for key to[8]"
+
+
+def test_invalid_index_key(spark):
+    with pytest.raises(ValueError) as error:
+        Runner(
+            spark,
+            config_path="tests/runner/overrider.yaml",
+            run_date="2023-03-31",
+            overrides={"runner.mail.test[8]": "test"},
+        )
+    assert error.value.args[0] == "Invalid key test"
+
+
+def test_invalid_key(spark):
+    with pytest.raises(ValueError) as error:
+        Runner(
+            spark,
+            config_path="tests/runner/overrider.yaml",
+            run_date="2023-03-31",
+            overrides={"runner.mail.test": "test"},
+        )
+    assert error.value.args[0] == "Invalid key test"