Sorted this out myself. For anyone else wanting the same this is how;
Replace all code is showthread_similarthreads with below;
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center">
<thead>
<tr>
<td class="tcat" width="100%" colspan="5">
<a style="float:$stylevar[right]" href="#top" onclick="return toggle_collapse('similarthreads')"><img id="collapseimg_similarthreads" src="$stylevar[imgdir_button]/collapse_tcat$vbcollapse[collapseimg_similarthreads].gif" alt="" border="0" /></a>
$vbphrase[similar_threads]<a name="similarthreads"></a> For: $thread[title]
</td>
</tr>
</thead>
<tbody id="collapseobj_similarthreads" style="$vbcollapse[collapseobj_similarthreads]">
</tr>
$similarthreadbits
</tbody>
</table>
<br />Replace all code is showthread_similarthreadbit with below;
<td class="alt1" align="$stylevar[left]"><span class="smallfont"><a href="showthread.php?$session[sessionurl]t=$simthread[threadid]" title="$simthread[preview]">$simthread[title]</a></span></td>This results in a 5 column X 1 row table showing only Thread Title with links.