Very, very close to conceding with nothing entered and not a clue what I was looking for. The "can be arranged" part of the instructions was particularly daunting, suggesting the clashes would have to be anagrammed. But the bottom right hand corner came to my rescue and both the theme words and the structure became crystal clear, with enough wow! factor to make the initial long slog worthwhile.
A rare example of the endgame being massively helpful in resolving ambiguities and speeding progress to the end.