17a. Distribution coming to an end? (6,3) ???I?G-?U? Doling Out?
14d. I have a discussion about a kind of tree (7) ?O???E? middle letter is 2nd letter 17a.
22a. Sort I used to find boring (7) ?E?C???
16d. Go up in public transport intended to take in others (5) no letters yet
19a. A short-cut (3) no letters but middle letter is 2nd letter of 16d