FWIW, I've had a few BTA's and powerheads attempting to occupy the same coordinates in space/time and I've always been amazed at how little tissue can actually regrow an anemone on top. I suppose there are never guarantees (I'll never know what happened to my old Rose BTA - just vanished one day after 4 years ... how does that happen??), but you just never know. I had this one clone of my brown BTA a few months ago completely obliterate itself and all that was left was a little bit of the foot, but it literally regrew a new anemone. Took a few months mind you, but it did come back from the brink. Weird stuff.
Mine went for a wicked walkabout too. All the way to the back of the rock and just peeking out ever so slightly.
But it stayed put there all day, so hopefully it's a spot to its liking.