Would it be possible to have delivery areas link to the delivery charge structure? Instead of looking for a minimum price, or by weight, it would convenient to have delivery costs based on certain locations/areas. Or, function as an additional cost.
For instance, delivering to a nearby location may cost 10£ due to the area, but a larger order may then make it free, whereas a further area may require a larger minimum order to cover the higher delivery charge.
Cheers,
Ben