Well, this was a rarity for me - fully solved, and before midday. Ok, I used the "Anagram" helper on this site for 16a, but the rest was All My Own Work :-)
3d made me laugh, so it's got to be COD. Not sure I can still quite parse 1d, but it fits.
1a and 26a use the same device, so if you've got one, it helps with the other.
V. enjoyable.