The plugin adds a
<a name="topic"></a>
immediately after the
<form id="new-post" action="https://gos.rewweb.co.uk/forums/forum/main-forum/2-2/" method="post" name="new-post">
I do this because I cannot guarantee that bbpress won’t change the name, so adding my own is more robust I feel.
If you are able to inspect then page you should see
<div id="new-topic-0" class="bbp-topic-form">
<form id="new-post" action="https://gos.rewweb.co.uk/forums/forum/main-forum/2-2/" method="post" name="new-post">
<a name="topic"></a>
Can you also confirm which versions of wordpress and bbpress you are using, and also list any plugins that affect bbpress