That worked fine - thanks. However ...
I will also be adding the option to add samples of fabric to the cart, for which there is no shipping charge. At present the shipping rules will apply the same charges to the samples as to the actual fabrics and I can't work out a way to apply an exception to them. Instead of shipping they will have a flat charge applied to them when someone orders more than 5. I assume that I can cater for that charge in the "Charge" section of the eCart Object but how do I get around the shipping issue?