Joomla Override for joomla.searchtools.grid.sort

Question

I would like to create an override for:

<?php echo JHtml::_('searchtools.sort', 'COM_BLA', 'b.id', $listDirn, $listOrder); ?>

I have put an Override into

.\administrator\components\com_mycomp\layouts\joomla\searchtools\grid\sort.php

but it's not working.

When i look at .\libraries\cms\html\searchtools.php i see that it returns:

JLayoutHelper::render('joomla.searchtools.grid.sort', $data);

So why is my override not working?