I learnt of that breed only through cryptic crosswords, where it makes rare appearances. Happened to suspect it here (2nd word more common in cryptics), so 1d was actually my FOI, a flying start. 😉
I'm thinking it's Vlad clueing that I'm just not getting. Been through loads of PMs in my mind but it's not sticking. Just one question. Is 15d a Latin phrase?