diff --git a/src/mx_bluesky/beamlines/i24/serial/fixed_target/i24ssx_moveonclick.py b/src/mx_bluesky/beamlines/i24/serial/fixed_target/i24ssx_moveonclick.py
index 59e03350f..2c03db728 100755
--- a/src/mx_bluesky/beamlines/i24/serial/fixed_target/i24ssx_moveonclick.py
+++ b/src/mx_bluesky/beamlines/i24/serial/fixed_target/i24ssx_moveonclick.py
@@ -12,8 +12,9 @@
 from dodal.devices.i24.pmac import PMAC
 from dodal.devices.oav.oav_detector import OAV
 
-from mx_bluesky.beamlines.i24.serial.fixed_target import \
-    i24ssx_Chip_Manager_py3v1 as manager
+from mx_bluesky.beamlines.i24.serial.fixed_target import (
+    i24ssx_Chip_Manager_py3v1 as manager,
+)
 from mx_bluesky.beamlines.i24.serial.fixed_target.ft_utils import Fiducials
 from mx_bluesky.beamlines.i24.serial.parameters.constants import OAV1_CAM
 
@@ -31,7 +32,7 @@ def _get_beam_centre(oav: OAV):
 
 def _calculate_zoom_calibrator(oav: OAV, RE: RunEngine):
     """Set the scale for the zoom calibrator for the pmac moves."""
-    currentzoom = RE(bps.rd(oav.zoom_controller.percentage)).plan_result
+    currentzoom = RE(bps.rd(oav.zoom_controller.percentage)).plan_result  # type: ignore
     zoomcalibrator = 1.547 - (0.03 * currentzoom) + (0.0001634 * currentzoom**2)
     return zoomcalibrator
 
diff --git a/tests/unit_tests/beamlines/i24/serial/fixed_target/test_moveonclick.py b/tests/unit_tests/beamlines/i24/serial/fixed_target/test_moveonclick.py
index b5bd3d69e..4084e5bd1 100644
--- a/tests/unit_tests/beamlines/i24/serial/fixed_target/test_moveonclick.py
+++ b/tests/unit_tests/beamlines/i24/serial/fixed_target/test_moveonclick.py
@@ -11,8 +11,7 @@
     update_ui,
 )
 
-# FIXME
-zoomcalibrator = 6
+ZOOMCALIBRATOR = 6
 
 
 @pytest.mark.parametrize(
@@ -20,18 +19,18 @@
     [
         (
             (15, 10),
-            "#1J:-" + str(15 * zoomcalibrator),
-            "#2J:-" + str(10 * zoomcalibrator),
+            "#1J:-" + str(15 * ZOOMCALIBRATOR),
+            "#2J:-" + str(10 * ZOOMCALIBRATOR),
         ),
         (
             (475, 309),
-            "#1J:-" + str(475 * zoomcalibrator),
-            "#2J:-" + str(309 * zoomcalibrator),
+            "#1J:-" + str(475 * ZOOMCALIBRATOR),
+            "#2J:-" + str(309 * ZOOMCALIBRATOR),
         ),
         (
             (638, 392),
-            "#1J:-" + str(638 * zoomcalibrator),
-            "#2J:-" + str(392 * zoomcalibrator),
+            "#1J:-" + str(638 * ZOOMCALIBRATOR),
+            "#2J:-" + str(392 * ZOOMCALIBRATOR),
         ),
     ],
 )
@@ -39,7 +38,7 @@
     "mx_bluesky.beamlines.i24.serial.fixed_target.i24ssx_moveonclick._get_beam_centre"
 )
 @patch(
-    "mx_bluesky.beamlines.i24.serial.fixed_target.i24ssx_moveonclick._get_beam_centre"
+    "mx_bluesky.beamlines.i24.serial.fixed_target.i24ssx_moveonclick._calculate_zoom_calibrator"
 )
 def test_onMouse_gets_beam_position_and_sends_correct_str(
     fake_zoom_calibrator: MagicMock,
@@ -50,10 +49,10 @@ def test_onMouse_gets_beam_position_and_sends_correct_str(
     pmac: PMAC,
     RE,
 ):
-    fake_zoom_calibrator.return_value = zoomcalibrator
+    fake_zoom_calibrator.side_effect = [ZOOMCALIBRATOR]
     fake_get_beam_pos.side_effect = [beam_position]
     fake_oav: OAV = MagicMock(spec=OAV)
-    RE(onMouse(cv.EVENT_LBUTTONUP, 0, 0, "", param=[pmac, fake_oav]))
+    onMouse(cv.EVENT_LBUTTONUP, 0, 0, "", param=[RE, pmac, fake_oav])
     mock_pmac_str = get_mock_put(pmac.pmac_string)
     mock_pmac_str.assert_has_calls(
         [