17A Tremble as panes are smashed in a dramatic way (13) I have ??A?E?P?A?E?N - tho am not sure of the second A, from 9D How value increases with gratitude (14), for which I have APPRECIATIVELY. 21A Judge caught by speed of introduction (7) ????A?E, the nearest I could get was PICRATE, which I'm sure is wrong. 26A Convenience, parking behind circuit (4), no letters yet. 15D No outsets develop in a smooth way (9), I have S?????U??, which looks like an anagram but I can't work it out, and 20D Betting war breaks out left of metropolis (6), I have ???A?? - could this be SPRAWL (as in urban sprawl)? I found this a bit tougher than usual today, so would really welcome a spot of help.
Thanks for all your help. Am almost done now. I now have P?E?A?E for 21A, which is now looking like PREFACE, tho I would have thought RATE would have cropped up somewhere in it.