Why in the SagePay payment module is 999999 used as a delivery code?  This is passed to SagePay in the cart as the delivery quantity.  I've set this to 1.

Line 232 in the SagePayPaymentProcessor class.

            if (order.OrderShippingInclTax > 0.0M)
            {
                // use code 999999 as the delivery code
                toReturn.AppendFormat(":Delivery:999999:{0:0.00}:{1:0.00}:{2:0.00}:{3:0.00}",
                    order.OrderShippingExclTax,
                    order.OrderShippingInclTax - order.OrderShippingExclTax,
                    order.OrderShippingInclTax,
                    order.OrderShippingInclTax
                    );
            }