Possible missing id on Perch Shop Cart - Discount with Tax

Hi,

I am trying to show my Perch Shop cart and am, I think, missing an id I need. I have:

Item Total - £139 - total_with_tax_formatted

Cart Discount - £27.80 - total_discounts_with_tax_formatted

Total (excluding delivery) - £92.67 - total_items_discounted_formatted

Shipping (expensive shipping) - £20.00 - shipping_with_tax_formatted

Grand Total - £131.20 - grand_total_formatted

The total excluding delivery needs to have tax added, otherwise it looks wrong. I can't see this in <perch:showall /> - after something like total_items_discounted_with_tax_formatted.

Thanks

Mike