Hi Brendan
I thought it might be, which means I have to revisit 3d! I thought it was an angram of "in ocean" with another letter. I'm trying a "G".
Thanks for hint for 21 ac. Got that now.
....and minutes later got 17d.
This still leaves me with 8d and 13ac. If my G is right for 3d, then there is only one word that fits, but I can't see the theme,
I've read Magpie Murders. Yes, it was quite good. I've just read a great book called American Dirt by Jeanine Cummins. I'd thoroughly recommend it.