You don't have an anemone problem, you have a clownfish problem.
Ocellaris and percula clowns are very unpredictable when it come to what they will choose as a host. BTAs and haddoni carpets are not their natural hosts, but sometimes the clowns will take to them immediately anyway. Other times it may take a long time (months/years) for them to accept the anemones. If they have found something else instead (your corals) they may never move into the anemones.
IME, saddleback(both black and brown) and true sebae clowns prefer haddoni over all other anemones. Clarki complex will accept a haddoni almost immediately, but if given a choice may prefer your BTA, or may swim back and forth. Tomato type clowns might prefer your BTA over the haddoni but will live in both. Skunk clowns are a bit of a toss up depending on which type of skunk.
I'm sorry that probably wasn't much help, unless you are willing to trade in your percs.