Kitten taken to climbing brick wall - busted claws

Hi, just after a bit of advice! 

My little princess has taken to climbing our interior brick wall. It's completely busted her claws, they're all split and frayed and dreadful. 

She did this a fair bit when we first got her, but since getting our second kitten, she stopped. The past few days she's started doing it again.

The first time, the vet recommended dousing her scratching post with catnip. We've done that, as well as built her a 6ft 5" cat tree with multiple climbing posts and scratching posts, which she also uses on occasion. 

Is there anything more we can do to stop her climbing the wall, or at least protect her claws? 

Could you try soft claws or a similar product? That way the claw cap would protect the claw.

If possable cover the wall with something

I'll look into something to cover her claws. It's not practical to cover the wall, as it's actually the chimney, so we can't put fabric or anything on it.