Really struggling. I agree with the others that this is a real killer!
2d D?N?I? - Fancy fellow on slalom sifting half a vintage port (6)
35d LEMON ???E?E - Spread things on lips to make you grimace and smile (5,6)
37d S?S???S?F?? - Electric power cust unless fuse replaced (11)
56a ??S???? - Dip in road that's part of course (7)