Free shipping over X working using discount code

Hello all, Nop 4.10 running Manual (Fixed or By Weight and By Total),
We have free shipping on orders over £20.00. If below this, then shipping is £3.00

If someone adds a product at £24.00 and then uses a discount code for £5.00 this totals £19.00 but the cart enables free shipping because the sub-total is £24.00.

How can the shipping be based on the cart total including discounts? Outside of discounts, the cart works correctly with any number of products or volume of a single one for the shipping.

Its just the use of the shipping being applied to the sub-total pre-discount that is causing issue.
Only one delivery provider, only two flat fees, free and £3.00

Many thanks

Which 'Discount type' are you using - Assigned to Products, Assigned to Order Total, Assigned to Order Subtotal?
The Fixed By Weight By Total plugin will calculate the sub total as the sum of cart item prices (including item/product discounts), but does not seem to account for discounts assigned to the order.  (Probably a short-sighted decision because of how it had to deal with items-per-warehouse shipping.)

It would need customization, or Shipping Director can do it using one of its variables:
$SubTotalWithoutDiscounts (uses orderTotalCalcService.GetShoppingCartSubTotal() )
$SubTotalWithDiscounts
$SubTotalWithoutDiscountsInclTax
$SubTotalWithDiscountsInclTax
$ProductTotalWithoutDiscounts (uses PriceCalculationService.GetSubTotal() )
$ProductTotalWithDiscounts

Your rules in Shipping Director would be:

Option
Free Shipping
[$SubTotalWithDiscounts] > 20.00
0.00

Option
Shipping
true
3.00