Hello. I bought this book after reading about it on mumsnet and am keen to put it into practice! Has anyone else followed this weight program? The author suggests getting getting 20lb adjustable ankle weights (roughly 10kg per leg). This is really heavy! I cant find anything above 5kg. I dont want to waste money getting the wrong weight if I do actually need the heavier ones - has anyone done it? (Or knows where I can get heavier weight....) Thanks.