I'm stuck on four, two of which I'm pretty sure I've got the correct answer but can't work out the wordplay. 15 across: There can be no number determined to reverse direction (7) ?E?D?S?
24 across: Extremely Secret Army avoiding ransom? It's irregular (6) I?M?S? (inmost?)
6 down: Those embarking on routine eleven irritating minutes late getting up to end of line (covered with more leaves) (6) ?L?I?R (elmier?)
15 down: They could be fair pushing up the turf, as the old fellow's doing (3) ??S
Thanks in advance