diff --git a/.github/workflows/build-test b/.github/workflows/build-test
index 4783a5d8..a726c0a1 100755
--- a/.github/workflows/build-test
+++ b/.github/workflows/build-test
@@ -45,7 +45,7 @@ python -m pip install --upgrade pip wheel build
 # Generate and install the package
 python -m build
 for w in dist/*.whl ; do
-    python -m pip install $w
+    python -m pip install $w[pecos,calendar]
     cp $w ${ARTIFACTSDIR}
 done
 
diff --git a/pytket/extensions/quantinuum/backends/calendar_visualisation.py b/pytket/extensions/quantinuum/backends/calendar_visualisation.py
index e0b4016f..fb0e87e7 100644
--- a/pytket/extensions/quantinuum/backends/calendar_visualisation.py
+++ b/pytket/extensions/quantinuum/backends/calendar_visualisation.py
@@ -42,9 +42,9 @@
 import calendar
 import datetime
 
-import matplotlib.pyplot as mpl  # type: ignore
+import matplotlib.pyplot as mpl
 import numpy as np
-from matplotlib.figure import Figure  # type: ignore
+from matplotlib.figure import Figure
 
 calendar.setfirstweekday(0)
 
diff --git a/pytket/extensions/quantinuum/backends/quantinuum.py b/pytket/extensions/quantinuum/backends/quantinuum.py
index 40d8bb56..1c82d21d 100644
--- a/pytket/extensions/quantinuum/backends/quantinuum.py
+++ b/pytket/extensions/quantinuum/backends/quantinuum.py
@@ -78,7 +78,7 @@
 from .api_wrappers import QuantinuumAPI, QuantinuumAPIError
 
 if TYPE_CHECKING:
-    import matplotlib  # type: ignore
+    import matplotlib
 
 try: