Ok firstly I created a little jscript function (which is held in one of my externally called jscript files)
function ACT_DropsearchBox(ar)
{
var strIDs = '<SELECT NAME="SX" style="font-size:10">';
var sel = " SELECTED";
for (var i=1;i<=ar.length;i++)
{
	if (ar[i].sURL !=null)
		{ 
		strIDs += '<OPTION VALUE="'+[i]+'">' + ar[i].sName + '</OPTION>';
		}
	}
	strIDs+='</SELECT>';
	return strIDs;
}

Next I altered my act_Primary.html so that it was generating the top sections that I needed (I have 5 main sections with quite a few products underneath) by adding NETQUOTEVAR:TOPLEVELSECTIONS_RAW

Next in my quick search area added
<FORM METHOD=GET ACTION="http://web106.aardvark-ipl.net/cgi-bin/ss003006.pl" target="CatalogBody">
        <A NAME="top">
	<INPUT TYPE=HIDDEN NAME="PAGE" VALUE="SEARCH">
        <span class="iprodent">Product Search</span>
	<script language=Javascript1.1>document.write(ACT_DropsearchBox(sections))</script>
        <INPUT TYPE=HIDDEN NAME=RANDOM VALUE="NETQUOTEVAR:RANDOM">
        </A>
        <INPUT NAME="SS" SIZE=12 MAXSIZE=255>&nbsp;
        <INPUT TYPE=HIDDEN NAME="TB" CHECKED VALUE="A">
	<script language="JavaScript">
			<!--
			for (nIndex = 0; nIndex < document.forms.length; nIndex++)
			  {
			  if (document.forms[nIndex] && document.forms[nIndex].SS)
			   {
	            	   document.forms[nIndex].SS.focus();
			   }
			  }
			 // -->
	 </script>
	<INPUT TYPE="HIDDEN" NAME="GB" VALUE="A">
        <INPUT TYPE=SUBMIT NAME=ACTION VALUE="Search">&nbsp;&nbsp;
      </FORM>

Now in actinic itself make sure search by sections is turned on!