I thought that I had got the word from 3B at the time, so I asked Harry in a forum post. He rightly blocked it, answered my question and made me laugh all at the same time. It never occurred to me that it was anything to do with 7B, and still did not until I started looking at this discussion thread in the last few days. The Cipher Challenge is already amazing, and these ‘hidden depths’ … we are so lucky to have it. May there be many more than 20 years!
[Thanks, I appreciate that! Always enjoy layering it up. Harry]