Midgler, my comment about internet research wasn't a complaint, but an observation. Yes, the Shackleton was definitely one that needed online research; the message from the across clues would mean nothing to anybody who didn't know the book, without that information certain aspects of the puzzle would be impossible. It might be possible to encode Row 9 from the message alone, but without knowing the source material the resulting word would mean nothing because you wouldn't know where to confirm it.
I started solving the Listener in the early 90s and I remember that ODQ, a decent encyclopaedia and my scant general knowledge were enough to confirm almost every theme, despite me being an even more rubbish solver then than I am now. These days puzzles rely far more on research than they used to - the layout of real tennis courts, a relatively obscure story by Rabelais, an old BBC hoax and the Kit Williams treasure hunt - all of which would take hours and hours of library research for those without internet access.
We live in the digital age and such a change is inevitable, which is why I don't complain about it. I just think it's time admit that anyone without internet is quite often at a disadvantage when solving the Listener.