Good afternoon, Elle!
The wind is wild here!
Stuff getting blown everywhere.
I understand what you mean with Royal Mail, but you did not employ them.
Marks and Spencers did, so let them know how you feel, and they can deal with them.
I found several new words as answers in my puzzle today.
11a, 22a, 23a, 25a, 17d.
And 15a is a dreadful homothingy.
But, I know the one you are stuck on.
"Half inch" means "pinch", as in "steal", apparently, and if you remove "l" for "large" and replace it with "W" for "Whiskey", there is a bird called "hawfinch".
In puzzles birds are often referred to as "singers".
Puzzle not too much of a tester today, I agree.