I woke up realising that, like Sunray, I had used one of my theme words in the wrong place. (11d for me). All sorted now.
Also woke up understanding the eight cell phrase and which letter to erase.
But ! Still don't see the three word phrase. I have the 12 letters, double checked, but can't make them into anything relevant. I have a V, but no K...is that right? A K would seem handy.
Gentle hint please?