Ok...let me see if I can help you out here...I have a tank with 9+ RBTAs and have been fortunate enough to basically have them all stay in one place...but it wasn't easy.
And from one newb (I consider myself a newb) to what seems like another, let me say that attempting to keep an anemone in one place is about as fruitless as playing the lottery with the expectation of ACTUALLY winning millions of dollars.
Every RBTA I've had has been different. They all look a bit different and have different "personalities" and therefore, they're all individual creatures and will behave as such. They're going to find a spot that's the most desirable for them.
While raising RBTAs, I've noticed a few things:
1) they like GOOD light...and will search high and low for the optimal place where they get JUST the right amount of light...too much light can fry an anemone (believe it or not)
2) they like medium flow; too much flow will drive them into undesirable places (i.e. you cannot see them)
3) they like holes and crevices so they can tuck their foot deep into a rock to protect it; an anemone's foot is like their heart...if it gets torn up, it can spell instant death. Luckily, tank-raised BTAs generally are hardy and can recover from most injuries (see two attached photos of one of my RBTA after a dance with a powerhead and her now).
4) they also need good water quality, which goes without saying basically...
If you provide all of that, then your nem will find a suitable place to situate itself and will do quite well....I apologize if that place is at the rear of your tank...but it's better to have a healthy anemone than one that dies and ruins your whole tank!
If you have any ?'s, don't hesitate to PM me...
Brock