Thanks all, including Paul. I reckon this was tough. I finished, but only by guessing what the first four letters of 8d might be, then seeing what came up in Chambers. Wouldn’t have got it otherwise (never heard of it)
Somewhat surprised to see 16d nominated as COD, which makes me think I’ve missed something. As far as I can tell, the definition is wrong (might have got away with it if plural) and the wordplay requires a double-letter that does not apply. Feels very loose to me, but I may be missing something