Roof, you will definitely know 23d, he's one of the most famous 16 amphibians ever:-)
4d - 4 letter "smile" + 1 letter "about" + 1 letter "goal in rugby" (the shape of the actual goal posts)
24d - is an anagram/'bananas' - this is a 16 you don't want to get angry:-)
6d - 3 letter gong" (think honours) goes around/'ringing' "out at first"
8d 2 letter "while" goes around 1 letter "special" and K - definition is "poses".
Hope that helps you make some headway.