Still struggling, despite the help! If you're still there Sarumite, I think I've gone wrong on 1d marchers who restored the flow of water (3,7) I've got "tap washers" but that now doesn't fit in with 10a, on which I am stuck.
10a Journalist became a member and was added afterwards (9) I've got S?W?O?NED
Help also on 17d I leave confusingly efficient operative (2,6) and 20d An artist has come up from a very dry place (6)