diff --git a/data/spot.py b/data/spot.py
index 8af0d15..56f2e78 100644
--- a/data/spot.py
+++ b/data/spot.py
@@ -133,6 +133,17 @@ class Spot:
     # The ID the source gave it, if any.
     source_id: str | None = None
 
+    def __post_init__(self):
+        """Normalise fields that don't survive a plain dict to Spot conversion. This is used in the "add spot" API
+        endpoint where the client is submitting JSON, and we want to recreate a full Spot object, including nested
+        objects such as the sig_refs list.."""
+
+        if self.sig_refs:
+            self.sig_refs = [
+                sig_ref if isinstance(sig_ref, SIGRef) else SIGRef(**sig_ref)
+                for sig_ref in self.sig_refs
+            ]
+
     def infer_missing(self, credentials=None):
         """Infer missing parameters where possible"""
 
diff --git a/server/handlers/api/addspot.py b/server/handlers/api/addspot.py
index f9eccd1..60c8762 100644
--- a/server/handlers/api/addspot.py
+++ b/server/handlers/api/addspot.py
@@ -1,4 +1,3 @@
-import json
 import logging
 import re
 from datetime import datetime
@@ -15,7 +14,6 @@ from core.lookup_helper import infer_band_from_freq
 from core.prometheus_metrics_handler import api_requests_counter
 from core.sig_utils import get_ref_regex_for_sig
 from core.utils import safe_json_dumps
-from data.sig_ref import SIGRef
 from data.spot import Spot
 
 
@@ -68,14 +66,6 @@ class APISpotHandler(tornado.web.RequestHandler):
             json_spot = tornado.escape.json_decode(post_data)
             spot = Spot(**json_spot)
 
-            # Converting to a spot object this way won't have coped with sig_ref objects, so fix that. (Would be nice to
-            # redo this in a functional style)
-            if spot.sig_refs:
-                real_sig_refs = []
-                for dict_obj in spot.sig_refs:
-                    real_sig_refs.append(json.loads(json.dumps(dict_obj), object_hook=lambda d: SIGRef(**d)))
-                spot.sig_refs = real_sig_refs
-
             # Reject if no timestamp, frequency, dx_call or de_call
             if not spot.time or not spot.dx_call or not spot.freq or not spot.de_call:
                 self.set_status(422)
diff --git a/templates/add_spot.html b/templates/add_spot.html
index f44407c..48eddee 100644
--- a/templates/add_spot.html
+++ b/templates/add_spot.html
@@ -76,7 +76,7 @@
 
 </div>
 
-<script src="/js/add-spot.js?v=1783701514"></script>
+<script src="/js/add-spot.js?v=1783701943"></script>
 <script>$(document).ready(function () {
     $("#nav-link-add-spot").addClass("active");
 }); <!-- highlight active page in nav --></script>
diff --git a/templates/alerts.html b/templates/alerts.html
index cde601a..b38c198 100644
--- a/templates/alerts.html
+++ b/templates/alerts.html
@@ -75,7 +75,7 @@
 
 </div>
 
-<script src="/js/alerts.js?v=1783701513"></script>
+<script src="/js/alerts.js?v=1783701943"></script>
 <script>$(document).ready(function () {
     $("#nav-link-alerts").addClass("active");
 }); <!-- highlight active page in nav --></script>
diff --git a/templates/bands.html b/templates/bands.html
index c3a1419..59614a9 100644
--- a/templates/bands.html
+++ b/templates/bands.html
@@ -75,8 +75,8 @@
 <script>
     let spotProvidersEnabledByDefault = {% raw json_encode(web_ui_options["spot-providers-enabled-by-default"]) %};
 </script>
-<script src="/js/spotsbandsandmap.js?v=1783701514"></script>
-<script src="/js/bands.js?v=1783701514"></script>
+<script src="/js/spotsbandsandmap.js?v=1783701943"></script>
+<script src="/js/bands.js?v=1783701943"></script>
 <script>$(document).ready(function () {
     $("#nav-link-bands").addClass("active");
 }); <!-- highlight active page in nav --></script>
diff --git a/templates/base.html b/templates/base.html
index 6c94a47..ee72525 100644
--- a/templates/base.html
+++ b/templates/base.html
@@ -1,6 +1,6 @@
 {% extends "skeleton.html" %}
 {% block head_extra %}
-<link rel="stylesheet" href="/css/style.css?v=1783701513" type="text/css">
+<link rel="stylesheet" href="/css/style.css?v=1783701943" type="text/css">
 <link href="/vendor/css/bootstrap-5.3.8.min.css" rel="stylesheet">
 <link href="/vendor/css/fontawesome-6.7.2.min.css" rel="stylesheet">
 <link href="/vendor/css/solid-6.7.2.min.css" rel="stylesheet">
@@ -10,10 +10,10 @@
 <script src="/vendor/js/bootstrap-5.3.8.bundle.min.js"></script>
 <script src="/vendor/js/tinycolor2-1.6.0.min.js"></script>
 
-<script src="/js/utils.js?v=1783701513"></script>
-<script src="/js/ui-ham.js?v=1783701513"></script>
-<script src="/js/geo.js?v=1783701513"></script>
-<script src="/js/common.js?v=1783701513"></script>
+<script src="/js/utils.js?v=1783701943"></script>
+<script src="/js/ui-ham.js?v=1783701943"></script>
+<script src="/js/geo.js?v=1783701943"></script>
+<script src="/js/common.js?v=1783701943"></script>
 {% end %}
 {% block body %}
 <div class="container">
diff --git a/templates/conditions.html b/templates/conditions.html
index 1811421..aa7e3b5 100644
--- a/templates/conditions.html
+++ b/templates/conditions.html
@@ -284,7 +284,7 @@
 </div>
 
 <script src="/vendor/js/chart-4.4.9.umd.min.js"></script>
-<script src="/js/conditions.js?v=1783701513"></script>
+<script src="/js/conditions.js?v=1783701943"></script>
 <script>$(document).ready(function () {
     $("#nav-link-conditions").addClass("active");
 }); <!-- highlight active page in nav --></script>
diff --git a/templates/map.html b/templates/map.html
index d4a9efe..47eb5a2 100644
--- a/templates/map.html
+++ b/templates/map.html
@@ -95,8 +95,8 @@
 <script>
     let spotProvidersEnabledByDefault = {% raw json_encode(web_ui_options["spot-providers-enabled-by-default"]) %};
 </script>
-<script src="/js/spotsbandsandmap.js?v=1783701513"></script>
-<script src="/js/map.js?v=1783701513"></script>
+<script src="/js/spotsbandsandmap.js?v=1783701943"></script>
+<script src="/js/map.js?v=1783701943"></script>
 <script>$(document).ready(function () {
     $("#nav-link-map").addClass("active");
 }); <!-- highlight active page in nav --></script>
diff --git a/templates/spots.html b/templates/spots.html
index efd41b4..3e34b08 100644
--- a/templates/spots.html
+++ b/templates/spots.html
@@ -116,8 +116,8 @@
 <script>
     let spotProvidersEnabledByDefault = {% raw json_encode(web_ui_options["spot-providers-enabled-by-default"]) %};
 </script>
-<script src="/js/spotsbandsandmap.js?v=1783701513"></script>
-<script src="/js/spots.js?v=1783701513"></script>
+<script src="/js/spotsbandsandmap.js?v=1783701943"></script>
+<script src="/js/spots.js?v=1783701943"></script>
 <script>$(document).ready(function () {
     $("#nav-link-spots").addClass("active");
 }); <!-- highlight active page in nav --></script>
diff --git a/templates/status.html b/templates/status.html
index 193dc93..e40d244 100644
--- a/templates/status.html
+++ b/templates/status.html
@@ -59,7 +59,7 @@
     </div>
 </div>
 
-<script src="/js/status.js?v=1783701514"></script>
+<script src="/js/status.js?v=1783701943"></script>
 <script>
     $(document).ready(function () {
         $("#nav-link-status").addClass("active");