What are these fools at English Heritage up to, it's not rocket science to work out that the image/map on the first page of their sixth update would be illegible onscreen (and not much better printed out). Thankfully, however, they've dropped the Mickey Mouse format of their previous updates and are now publishing something with a bit more meat on it (I say 'bit more' because the info coming out really is vague and amateurish). Consequently, slumpy, even if I could I can't answer your question re: "Does this second bank mean two banks with a ditch between them..." Perhaps someone from English Heritage's esteemed 'Silbury Hill Conservation Project archaeological team' could address the question here... English Heritage, you have an audience of informed contributors on TMA waiting for clear and accurate information on your activities and finds at Silbury - do it!