18 across: Carriage lane cut by me and you, say (6)
It took some fiddling and some scratching of heads until it was realised that me referred to DA himself (we’ve always gotten the impression that he’s a he), so that we end up having landau = carriage, lane cut = lan, me = da and you say = u.
4 down: A metal prolonged perfect metal (8)
This was earmarked for the DA Confusion category, but I managed to figure out that it’s quite a quality clue for a = a, metal = tin, perfect = plum and metal = platinum.
9 across: Guy’s g’days (3)
A quality piece of double-meaning cuteness. One of his best.