I feel your pain.
I also have a anemone that is going bonkers. It didn't start growing like crazy until I got a
maroon clown for it.
I had read in a thread where a guy had some LR fall on his anemone and it tore the tissue. This caused the anemone to drop the torn tissue and a new anemone was born.
Well knowing that I decided to take a pair of scissors and made a 1inch long wedge looking cut into mine hoping it would split. Well it healed in just a couple days and now a little over two weeks it does not look like it is going to spit, actually spread out further.
It is attached to a piece of LR at the bottom of my aquascape so there is no way for me to pull the rock out to get him off. I may have to try and peel him off and offer him for sale or see if a local LFS can sell him. I hate to do it since I have had it for almost 4 years.
Sam