39d is just a normal clue and the definition is "pitch invaders" (usually unclothed). for 17d the first two words define the 7-letter part of the answer and the next two are an anagram of the 6 letter part if you change "six" to its Latin equivalent.
I am stuck on my last answer for 47d. I presume the answer means both a "track official" and an item on a menu and the symbol has to go in the third square but I can't find a symbol which could represent its 4 letters. Any help appreciated.