Rock anemones do not host clowns, they have the potential to kill a clown. Not uncommon for LPS to host clowns but sometimes to the detriment of the coral.
Factually clowns only host parasites, anemones and corals host clowns, but anywho, some large polyp corals become stressed over time, do not open to their full potential and may eventually die off from the stress of a clown residing. What type of clown do you have?
She may very well become too large to reside in LPS without doing long term damage. You can try a BTA (bubble tip anemone) and see if she will reside there. Try to get a larger BTA if possible though.
I have the same problem. My female started using a colony of Magician Palys first, then some Sunny D's zoas and now my fairly large goniopora. The male is trying to use a small duncan colony for a host. So far no damage but I didn't forsee this coming.