[PhilJ]

Michael, in skin/reboot/customer/main/search_sort_by.tpl

Replace...

    <option{if $name eq $selected && $sort_direction eq 0} selected="selected"{/if} value="{$url}&amp;sort={$name|amp}&amp;sort_direction=0" class="sort_asc">{$field} &uarr;</option>
    <option{if $name eq $selected && $sort_direction eq 1} selected="selected"{/if} value="{$url}&amp;sort={$name|amp}&amp;sort_direction=1" class="sort_desc">{$field} &darr;</option>

With...

    <option{if $smarty.get.sort eq $name && $smarty.get.sort_direction eq 0} selected="selected"{/if} value="{$url}&amp;sort={$name|amp}&amp;sort_direction=0" class="sort_asc">{$field} &uarr;</option>
    <option{if $smarty.get.sort eq $name && $smarty.get.sort_direction eq 1} selected="selected"{/if} value="{$url}&amp;sort={$name|amp}&amp;sort_direction=1" class="sort_desc">{$field} &darr;</option>

This works for me, try the demo. Thanks for reporting.