I now have a completed grid, a work area (that I wouldn't normally think of as such a thing), a possible perp (thanks, notrab - I would never have spotted that!) and yes, I also worked out the 'tone' of the 'work area', which is indicated in the preamble.
But I'm stuck. The second part of the instruction points us to what I take to be seven letters (the other two in the trail aren't as described in the instruction) that must be arranged in a column. I can see some possible phrases but none that would make sense in a column, assuming something has to go before or after them - otherwise, what would be the point?
There's a word in the top row that must be more than a coincidence as well. Something that should be given to the perp to persuade him not to create scatological 'messes'? But The Listener disapproves of poor taste, doesn't it?