15d) Tchaikovsky fairy's sweet (9) S????????
17d) Half of Roman York's revolutionary mantle (4) R???
18d) Authorised boffin's wings to be clipped, one in Argentina (8) no letters
19a) Tornado, say, right before new doctor comes in (7,6) ??????R ?????R
23a) Irish girl gets into trouble, creating annoyance (10) ??????T????
All help greatly appreciated.