diff --git a/NHSUKViewComponents.Web/ViewComponents/ErrorSummaryViewComponent.cs b/NHSUKViewComponents.Web/ViewComponents/ErrorSummaryViewComponent.cs
index 3bde6ee..2fca724 100644
--- a/NHSUKViewComponents.Web/ViewComponents/ErrorSummaryViewComponent.cs
+++ b/NHSUKViewComponents.Web/ViewComponents/ErrorSummaryViewComponent.cs
@@ -13,9 +13,23 @@ public IViewComponentResult Invoke(string[]? orderOfPropertyNames)
                 .SelectMany(kvp => kvp.Value.Errors.Select(e => new ErrorSummaryListItem(kvp.Key, e.ErrorMessage)))
                 .ToList();
 
+            var groupingMetadata = ViewData["GroupedFormControlMetadata"] as Dictionary<string, bool>;
+
+            foreach (var error in errors)
+            {
+                string key = error.Key;
+                bool isGrouped = groupingMetadata != null && groupingMetadata.ContainsKey(key) && groupingMetadata[key];
+
+                if (isGrouped)
+                {
+                    error.Key += "-0";
+                }
+            }
+
             var orderedErrors = GetOrderedErrors(errors, orderOfPropertyNames ?? new string[0]);
 
             var errorSummaryViewModel = new ErrorSummaryViewModel(orderedErrors);
+
             return View(errorSummaryViewModel);
         }
 
diff --git a/NHSUKViewComponents.Web/Views/Shared/Components/RadioList/Default.cshtml b/NHSUKViewComponents.Web/Views/Shared/Components/RadioList/Default.cshtml
index eddfb33..c901ebd 100644
--- a/NHSUKViewComponents.Web/Views/Shared/Components/RadioList/Default.cshtml
+++ b/NHSUKViewComponents.Web/Views/Shared/Components/RadioList/Default.cshtml
@@ -52,7 +52,7 @@
             @foreach (var (radio, index) in Model.Radios.Select((r, i) => (r, i)))
             {
                 counter = index;
-                var radioId = $"{radio.Value}-{index}";
+                var radioId = $"{Model.AspFor}-{index}";
                 if (!string.IsNullOrWhiteSpace(Model.Class))
                 {
                     <div class="@Model.Class">
@@ -106,7 +106,7 @@
             @if (Model.OptionalRadio != null)
             {
                 <div class="nhsuk-radios__divider nhsuk-u-padding-left-2">or</div>
-                var radioId = $"{Model.OptionalRadio.Value}-{++counter}";
+                var radioId = $"{Model.AspFor}-{++counter}";
                 <div class="nhsuk-radios__item">
                     <input class="nhsuk-radios__input"
                            id="@radioId"