Well the return key was updating the cart but then ......
only updates the cart in Internet Explorer when there is more than one different item. Still works in Safari, Firefox and Chrome.
<input type="submit" name="eCart1_Update_100" id="eCart1_Update_100" value="Update" alt="Update" class="eC_FormButton" style="float:right;margin-left:3px;"/>
This code is still before the checkout, continue and empty buttons code.
Any ideas?