So would this be okay?

<a href="{$link->getModuleLink('realexredirect', 'payment',array(),'true')|escape:'htmlall':'UTF-8'}" title="{l s='Pay by Credit or Debit Card' mod='realexredirect'}">
<p class="payment_module realexredirect">    
    {l s='Pay by CB card with Realex Payments' mod='realexredirect'}    
</p>
</a>

This works with PrestaShop 1.5 also.