I have just finished this, picking it up on the back of your post. An enjoyable read (so thank you), but have to agree with your "disorganised ending" description - the last chapters seemed somewhat rushed and only fleeting reference being made to one or two significant events. I too will continue with the series - I have the library app, so can borrow most books electronically and saves a packet.
I had read some of his non Harry Hole books, all equally enjoyable.
Awesome book if you can get used to the set up, statues, halls etc.
Just read this then David Mitchell's Utopia Avenue. He's such a good writer.
I read Mitchell's The thousand autumns of Jacob de Zoet a few years ago, so will put Utopia on the list.
The Meaning of Night - Michael Cox