Before I try and make sense of the endgame, can I get help with a couple of parse, I have the answers but can't see all the wordplay ...
17d - Nancy’s child cycling bog hasn’t sufficient power (6)
My answer is "Nancy's child" made up of a 3 letter "bog" 'cycled' but I can't see how the last 3 letters + the extra one are derived from "hasn't sufficient power"?
18d - Adjutant’s party raised short cheer in the van (6)
I have the definition as an "adjutant" with the last 4 letters a "party" but my problem is with the first two in the front/'in the van' - I have AR which looks like RA(h) for "cheer" reversed/raised but if the removal of the H is because the clue says "short cheer" then where is the extra letter?
PS I'm going to get some much needed sleep so won't be able to reply until tomorrow (actually, it's already tomorrow so later today!)