Took a long time to get going on this. Initially I thought it was harder than usual, but eventually it speeded up (getting 8d was very helpful!) and everything fell into place. Apart, that is, from 10a, which I had to put into crossword solver, and even then I didn't initially get it. The word was unknown to me, as was the 'somewhere in Bolivia'.
COD was 14d - made me smile. Also liked 20a. Thanks Everyman.