Upset plans (5,1,7,2,3,5)

I believe the answer is:
throw a spanner in the works
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">upset plans</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for throw a spanner in the works that I've seen before include "Upset plans (5,1,7,2,3,5)" , "cause upset" .)