diff --git a/src/dodal/devices/robot.py b/src/dodal/devices/robot.py
index 0acb6e6eaf..52e3b478cf 100644
--- a/src/dodal/devices/robot.py
+++ b/src/dodal/devices/robot.py
@@ -43,6 +43,9 @@ class SampleLocation:
     pin: int
 
 
+SAMPLE_LOCATION_EMPTY = SampleLocation(-1, -1)
+
+
 class PinMounted(StrictEnum):
     NO_PIN_MOUNTED = "No Pin Mounted"
     PIN_MOUNTED = "Pin Mounted"
@@ -61,7 +64,7 @@ async def raise_if_error(self, raise_from: Exception):
             raise RobotLoadError(int(error_code), error_string) from raise_from
 
 
-class BartRobot(StandardReadable, Movable[SampleLocation | None]):
+class BartRobot(StandardReadable, Movable[SampleLocation]):
     """The sample changing robot."""
 
     # How long to wait for the robot if it is busy soaking/drying
@@ -179,16 +182,16 @@ async def _load_pin_and_puck(self, sample_location: SampleLocation):
         await self.pin_state_or_error()
 
     @AsyncStatus.wrap
-    async def set(self, value: SampleLocation | None):
+    async def set(self, value: SampleLocation):
         """
         Perform a sample load from the specified sample location
         Args:
-            value: The pin and puck to load, or None to unload the sample.
+            value: The pin and puck to load, or SAMPLE_LOCATION_EMPTY to unload the sample.
         Raises:
-            RobotLoadError if a timeout occurs, or if an error occurs loading the smaple.
+            RobotLoadError if a timeout occurs, or if an error occurs loading the sample.
         """
         try:
-            if value is not None:
+            if value != SAMPLE_LOCATION_EMPTY:
                 await wait_for(
                     self._load_pin_and_puck(value),
                     timeout=self.LOAD_TIMEOUT + self.NOT_BUSY_TIMEOUT,
diff --git a/tests/devices/test_bart_robot.py b/tests/devices/test_bart_robot.py
index 59a9184003..abcb2179cd 100644
--- a/tests/devices/test_bart_robot.py
+++ b/tests/devices/test_bart_robot.py
@@ -14,6 +14,7 @@
 )
 
 from dodal.devices.robot import (
+    SAMPLE_LOCATION_EMPTY,
     WAIT_FOR_NEW_PIN_MSG,
     WAIT_FOR_OLD_PIN_MSG,
     BartRobot,
@@ -253,7 +254,7 @@ async def test_moving_the_robot_will_reset_error_if_light_curtain_is_tripped_and
 async def test_unloading_the_robot_waits_for_drying_to_complete(robot_for_unload):
     robot, trigger_completed, drying_completed = robot_for_unload
     drying_completed.set()
-    unload_status = robot.set(None)
+    unload_status = robot.set(SAMPLE_LOCATION_EMPTY)
 
     await asyncio.sleep(0.1)
     assert not unload_status.done
@@ -269,7 +270,7 @@ async def test_unloading_the_robot_times_out_if_unloading_takes_too_long(
 ):
     robot, trigger_completed, drying_completed = robot_for_unload
     drying_completed.set()
-    unload_status = robot.set(None)
+    unload_status = robot.set(SAMPLE_LOCATION_EMPTY)
 
     with pytest.raises(RobotLoadError) as exc_info:
         await unload_status
@@ -280,7 +281,7 @@ async def test_unloading_the_robot_times_out_if_unloading_takes_too_long(
 async def test_unloading_the_robot_times_out_if_drying_takes_too_long(robot_for_unload):
     robot, trigger_completed, drying_completed = robot_for_unload
     trigger_completed.set()
-    unload_status = robot.set(None)
+    unload_status = robot.set(SAMPLE_LOCATION_EMPTY)
 
     with pytest.raises(RobotLoadError) as exc_info:
         await unload_status