"Ham" was being dropped because browser autofill started volunteering
people's actual surnames in the hidden spam trap field.

registration-form.md

@@ -15,8 +15,8 @@ your details, and someone will get back to you shortly via email. If you receive
 <div class="formgroup">
 <label for="name">Name <i>(optional)</i></label>
 <input id="name" name="name" type="text" maxlength="40">
-<label for="surname">This should be left unchanged</label>
-<input id="surname" name="surname" type="text" maxlength="40">
+<label for="emptyfield">This should be left unchanged</label>
+<input id="emptyfield" name="emptyfield" type="text" maxlength="40">
 
 <label for="email">Contact email address</label>
 <input id="email" name="email" type="email" required>