Thanks JimC, I couldn't see that for looking.
I have Ken James, he used to be around some years ago, haven't seen him for a while. What about 26 across: Spend time with singer heard in the ocean (3-4) s?a-???s
"poetry can be a very difficult concept to understand" ... may be entropy = anagram of 'poetry' & 'n' although I don't understand where the 'n' comes from.