diff --git a/l10n_be_cooperator_national_number/models/res_partner.py b/l10n_be_cooperator_national_number/models/res_partner.py
index 47550c8d2..7beea89a8 100644
--- a/l10n_be_cooperator_national_number/models/res_partner.py
+++ b/l10n_be_cooperator_national_number/models/res_partner.py
@@ -2,7 +2,10 @@
 #
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
+from collections import namedtuple
+
 from odoo import api, models
+from odoo.exceptions import ValidationError
 
 
 class ResPartner(models.Model):
@@ -32,7 +35,26 @@ def get_be_national_register_number(self):
             return id_number.name
         return None
 
-    def update_belgian_national_number(self, national_number):
+    @api.model
+    def validate_be_national_register_number(self, national_number, error=False):
+        """Verify whether the national number is valid. Returns True if valid.
+
+        If error is True, a ValidationError is raised instead.
+        """
+        belgian_cat = self.sudo().get_be_national_register_number_id_category()
+        # The validation function expects an id_number record. We don't have
+        # that yet, so we'll mock one.
+        IdNumber = namedtuple("ResPartnerIdNumber", ["name"])
+        id_number = IdNumber(national_number)
+        try:
+            belgian_cat.validate_id_number(id_number)
+        except ValidationError:
+            if error:
+                raise
+            return False
+        return True
+
+    def update_be_national_register_number(self, national_number):
         self.ensure_one()
         result = None
         if national_number:
diff --git a/l10n_be_cooperator_national_number/models/subscription_request.py b/l10n_be_cooperator_national_number/models/subscription_request.py
index 52bc63129..217ff56ff 100644
--- a/l10n_be_cooperator_national_number/models/subscription_request.py
+++ b/l10n_be_cooperator_national_number/models/subscription_request.py
@@ -2,7 +2,6 @@
 #
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
-from collections import namedtuple
 
 from odoo import _, api, fields, models
 from odoo.exceptions import UserError
@@ -33,26 +32,18 @@ def _compute_require_national_number(self):
                 request.company_id.get_require_national_number(request.is_company)
             )
 
-    @api.model
-    def check_be_national_register_number(self, national_number):
-        national_number_id_category = self.env[
-            "res.partner"
-        ].get_be_national_register_number_id_category()
-        # this function checks the value of id_number.name, not id_number
-        # directly.
-        id_number = namedtuple("id_number", ("name"))(national_number)
-        national_number_id_category.validate_id_number(id_number)
-
     def validate_subscription_request(self):
         self.ensure_one()
         if self.require_national_number and not self.national_number:
             raise UserError(_("National Number is required."))
         if self.national_number:
-            self.check_be_national_register_number(self.national_number)
+            self.env["res.partner"].validate_be_national_register_number(
+                self.national_number, error=True
+            )
         invoice = super().validate_subscription_request()
         if not self.is_company:
             partner = invoice.partner_id
-            partner.update_belgian_national_number(self.national_number)
+            partner.update_be_national_register_number(self.national_number)
         return invoice
 
     def set_person_info(self, partner):
diff --git a/l10n_be_cooperator_national_number/readme/newsfragments/136.misc.1.rst b/l10n_be_cooperator_national_number/readme/newsfragments/136.misc.1.rst
new file mode 100644
index 000000000..5cb3378d3
--- /dev/null
+++ b/l10n_be_cooperator_national_number/readme/newsfragments/136.misc.1.rst
@@ -0,0 +1,4 @@
+``check_be_national_register_number`` moved from ``subscription.request`` to
+``res.partner`` and renamed to ``validate_be_national_register_number``. Added
+``error`` kwarg, and it is no longer necessary to call this method with
+``sudo()``.
diff --git a/l10n_be_cooperator_national_number/readme/newsfragments/136.misc.2.rst b/l10n_be_cooperator_national_number/readme/newsfragments/136.misc.2.rst
new file mode 100644
index 000000000..9c3aecb7d
--- /dev/null
+++ b/l10n_be_cooperator_national_number/readme/newsfragments/136.misc.2.rst
@@ -0,0 +1,2 @@
+``update_belgian_national_number`` renamed to
+``update_be_national_register_number``.
diff --git a/l10n_be_cooperator_website_national_number/controllers/main.py b/l10n_be_cooperator_website_national_number/controllers/main.py
index 75b1104f4..6271768dd 100644
--- a/l10n_be_cooperator_website_national_number/controllers/main.py
+++ b/l10n_be_cooperator_website_national_number/controllers/main.py
@@ -1,4 +1,3 @@
-from odoo.exceptions import ValidationError
 from odoo.http import request
 from odoo.tools.translate import _
 
@@ -37,14 +36,16 @@ def _additional_validate(self, kwargs, logged, values, post_file):
             return result
         national_number = values.get("national_number")
         if national_number:
-            try:
-                # sudo is required to allow access to res.partner.id_category.
-                request.env[
-                    "subscription.request"
-                ].sudo().check_be_national_register_number(values["national_number"])
+            valid = request.env["res.partner"].validate_be_national_register_number(
+                values["national_number"]
+            )
+            if not valid:
+                values["error_msg"] = (
+                    _("%s is not a valid Belgian national registration number")
+                    % values["national_number"]
+                )
+            else:
                 return True
-            except ValidationError as ve:
-                values["error_msg"] = str(ve)
         else:
             is_company = kwargs.get("is_company") == "on"
             if not request.env.company.get_require_national_number(is_company):