Shipping Cost per item

Asked for this often enough for it to be worth making a feature request

Allow admin to set up a shipping cost that increments a value depending on the number of items in the order, in addition to costs decided by weight or volume or price.

Example 1
If the standard shipping is £10 for items weighing between 500g and 999g and there was an additional cost of £1.50 per item

An order for 3 items weighting 501g in total would cost £10 + (£1.5 × 3 = £14.50)

Example 2
If the standard shipping is £10 for items weighing between 500g and 999g and there was an additional cost of £1.50 per item after the first item

An order for 3 items weighting 501g in total would cost £10 + (£1.50 × 2 = £13)

Gary