I'm not enjoying this one today. The answers don't seem elegant or it may be because I'm well and truly stuck and can't solve them.
28 across. clue: Modern opera taking place in empty La Fenice recalled (2,4). I have: E? N?N?
5 across, clue: Alarms first to last showing a nice touch (6).
18 down, clue: You may get stuck on this one! (8). I have: ?D???I??
8 down, clue: Announcement about leave in Washington office (5, 10). I have: ??A?E ???A???E??
Help please.