8a. Sound of a river embankment taking its toll?(4) = -e--
11a. Silent order to join forces....(6) answer = ------
18a. These are the daydreams we build for keeps.(7,2,3,3) answer = -a-t---i-------...
2d. How the supreme Roman god might have self-exclaimed?"(2,4) = El---e
10a. Greek beast in myth? A lot of bull, man!(8) = -i------
4d. some box erected for show-jumpers to clear(4) = -x--...