The example pp 306 – there solution ends with 1000 gift aid unrelieved (over two years) and a TTP of 29,500 in y/e 30/11/12.
If one carry’s all the loss (20,000) forward then none of the Gift Aid is unrelieved and the total taxable profits over the three years is 28,500 as compared to 29,500 with 1000 of gift aid not relieved!!!!