Question Author
Well done, MargoTester.
There are 3 practicable 5-letter grid positions, but one of them can be eliminated as its 2nd letter (15) is doubled in a 5-letter word nearby. It's then impossible for that letter to be a U.
After that it's not difficult to make the correct choice by counting the frequency of the two possible Es (9 & 17). Getting the rest of the puzzle out is quite simple after that. (It is assessed as 6/10 for difficulty.)