Ok, so her stripes are still there. I have tried keeping the light off more, I have limited the amount of time I have the bubbles on and I've added more places for her to hide.
She isn't acting strangely, out of all of my betta she is the most interactive, if I go remotely near her tank she's already at the front before I've gotten half way across the room, she doesn't hide at all. She's pretty much always active and she eats ferociously! She's not really showing any signs of stress apart from the stripes.
Could they be part of her natural coloration? I've read the more wild breeds have stripes all the time, betta Picta for example.
I know she was imported from Singapore.
Am now wondering if she could possibly be from a strain of wild betta.