Thanks Alex,

I did something slightly different. Basically because I was not aware of your solution then.

in main tpl I changed:

{if $subtemplate}
{include file="$template/subtemplates/$subtemplate"}
{else}
{$content|default:""}
{/if}

To:

{if $subtemplate=="index_table.tpl.inc"}
{include file="$template/subtemplates/index.tpl.inc"}
{elseif $subtemplate}
{include file="$template/subtemplates/$subtemplate"}
{else}
{$content|default:""}
{/if}