Nice one! Definitely section Hyalosema, to me looks closest to Bulb. singulare or Bulb. bandischii but I'm not too familiar with the section...
--Nat
Hi Nat,
yeah they look very similar. i cant tell them apart from comparing the pictures. i think it is a Bulbophyllum singulare though because it's sepals are not fuzzy as mentioned in IOSPE photos.