I struggled with this, never got on the wavelength. Mistakenly reversed wordplay in 13d, which cost a lot of time.
FOI 19d, LOI 3.
Needed Google for one unfamiliar acronym.
No clear COD, but candidate list includes 1d (on which a misdirection error cost time), 11, 4, 17, 10, 18, 19d.
Thanks to Boatman.