diff --git a/bilby/gw/prior.py b/bilby/gw/prior.py
index 1b51fef564792a208b03a9916bdd11d1607c1dd0..375124147a1dbbbb36e972dc0f0cda15adb969c1 100644
--- a/bilby/gw/prior.py
+++ b/bilby/gw/prior.py
@@ -20,13 +20,17 @@ class Cosmological(Interped):
     _default_args_dict = dict(
         redshift=dict(name='redshift', latex_label='$z$', unit=None),
         luminosity_distance=dict(
-            name='luminosity_distance', latex_label='$d_L$', unit='Mpc'),
+            name='luminosity_distance', latex_label='$d_L$', unit=units.Mpc),
         comoving_distance=dict(
-            name='comoving_distance', latex_label='$d_L$', unit='Mpc'))
+            name='comoving_distance', latex_label='$d_C$', unit=units.Mpc))
 
     def __init__(self, minimum, maximum, cosmology=None, name=None,
                  latex_label=None, unit=None):
         self.cosmology = get_cosmology(cosmology)
+        if name not in self._default_args_dict:
+            raise ValueError(
+                "Name {} not recognised. Must be one of luminosity_distance, "
+                "comoving_distance, redshift".format(name))
         self.name = name
         label_args = self._default_args_dict[self.name]
         if latex_label is not None:
@@ -35,7 +39,7 @@ class Cosmological(Interped):
             if isinstance(unit, str):
                 unit = units.__dict__[unit]
             label_args['unit'] = unit
-        self.unit = unit
+        self.unit = label_args['unit']
         self._minimum = dict()
         self._maximum = dict()
         self.minimum = minimum
@@ -138,12 +142,6 @@ class Cosmological(Interped):
 
 class UniformComovingVolume(Cosmological):
 
-    def __init__(self, minimum, maximum, cosmology=None,
-                 name='luminosity_distance', latex_label='$d_L$', unit='Mpc'):
-        Cosmological.__init__(
-            self, minimum=minimum, maximum=maximum, cosmology=cosmology,
-            name=name, latex_label=latex_label, unit=unit)
-
     def _get_redshift_arrays(self):
         zs = np.linspace(self._minimum['redshift'] * 0.99,
                          self._maximum['redshift'] * 1.01, 1000)
diff --git a/test/gw_prior_test.py b/test/gw_prior_test.py
index a3bf4e6891755677d000380f3286e01002a8e0b2..f7c7454e9472f496b048045e1719b23f08321cfa 100644
--- a/test/gw_prior_test.py
+++ b/test/gw_prior_test.py
@@ -79,31 +79,34 @@ class TestUniformComovingVolumePrior(unittest.TestCase):
         pass
 
     def test_minimum(self):
-        prior = bilby.gw.prior.UniformComovingVolume(minimum=10, maximum=10000)
+        prior = bilby.gw.prior.UniformComovingVolume(
+            minimum=10, maximum=10000, name='luminosity_distance')
         self.assertEqual(prior.minimum, 10)
 
     def test_maximum(self):
-        prior = bilby.gw.prior.UniformComovingVolume(minimum=10, maximum=10000)
+        prior = bilby.gw.prior.UniformComovingVolume(
+            minimum=10, maximum=10000, name='luminosity_distance')
         self.assertEqual(prior.maximum, 10000)
 
     def test_zero_minimum_works(self):
-        prior = bilby.gw.prior.UniformComovingVolume(minimum=0, maximum=10000)
+        prior = bilby.gw.prior.UniformComovingVolume(
+            minimum=0, maximum=10000, name='luminosity_distance')
         self.assertEqual(prior.minimum, 0)
 
     def test_specify_cosmology(self):
         prior = bilby.gw.prior.UniformComovingVolume(
-            minimum=10, maximum=10000, cosmology='Planck13')
+            minimum=10, maximum=10000, name='luminosity_distance',
+            cosmology='Planck13')
         self.assertEqual(repr(prior.cosmology), repr(cosmology.Planck13))
 
     def test_comoving_prior_creation(self):
         prior = bilby.gw.prior.UniformComovingVolume(
-            minimum=0.1, maximum=1, name='comoving_distance',
-            latex_label='$d_C$')
+            minimum=10, maximum=1000, name='comoving_distance')
         self.assertEqual(prior.latex_label, '$d_C$')
 
     def test_redshift_prior_creation(self):
         prior = bilby.gw.prior.UniformComovingVolume(
-            minimum=0.1, maximum=1, name='redshift', latex_label='$z$')
+            minimum=0.1, maximum=1, name='redshift')
         self.assertEqual(prior.latex_label, '$z$')
 
     def test_redshift_to_luminosity_distance(self):
@@ -113,12 +116,14 @@ class TestUniformComovingVolumePrior(unittest.TestCase):
         self.assertEqual(new_prior.name, 'luminosity_distance')
 
     def test_luminosity_distance_to_redshift(self):
-        prior = bilby.gw.prior.UniformComovingVolume(minimum=10, maximum=10000)
+        prior = bilby.gw.prior.UniformComovingVolume(
+            minimum=10, maximum=10000, name='luminosity_distance')
         new_prior = prior.get_corresponding_prior('redshift')
         self.assertEqual(new_prior.name, 'redshift')
 
     def test_luminosity_distance_to_comoving_distance(self):
-        prior = bilby.gw.prior.UniformComovingVolume(minimum=10, maximum=10000)
+        prior = bilby.gw.prior.UniformComovingVolume(
+            minimum=10, maximum=10000, name='luminosity_distance')
         new_prior = prior.get_corresponding_prior('comoving_distance')
         self.assertEqual(new_prior.name, 'comoving_distance')
 
diff --git a/test/prior_test.py b/test/prior_test.py
index aeb6a24b856685e1360d74a1460c95d3e47063c5..d8d4041de3a719e4a4238945f60e522b3a641388 100644
--- a/test/prior_test.py
+++ b/test/prior_test.py
@@ -133,7 +133,7 @@ class TestPriorClasses(unittest.TestCase):
             bilby.core.prior.PowerLaw(name='test', unit='unit', alpha=2, minimum=1, maximum=1e2),
             bilby.core.prior.Uniform(name='test', unit='unit', minimum=0, maximum=1),
             bilby.core.prior.LogUniform(name='test', unit='unit', minimum=5e0, maximum=1e2),
-            bilby.gw.prior.UniformComovingVolume(name='redshift', unit=None, minimum=0.1, maximum=1.0),
+            bilby.gw.prior.UniformComovingVolume(name='redshift', minimum=0.1, maximum=1.0),
             bilby.core.prior.Sine(name='test', unit='unit'),
             bilby.core.prior.Cosine(name='test', unit='unit'),
             bilby.core.prior.Interped(name='test', unit='unit', xx=np.linspace(0, 10, 1000),