A simple (but possibly ethically grey) solution would be to offer to your DD to sell them on Ebay or Gumtree and directly give her the cash that you get for them. Given that they're £170 new, if worn once you should be able to get about £100, easy. Your DD gets that £100, maybe spread out into installments (does she have her own bank account yet?) so she can't blow it all at once.
That way she can choose between stripper boots (eyeroll) or a real chunk of cash to blow on things she really wants. If you don't want to hand over the cash direct, you can promise her to put that £100 towards anything she wants when she wants it. Maybe keep a record on a post-it on the fridge e.g. £5 spent on magazine, £10 spent on pizza etc etc, until the £100 has been reached. Gives her a nice lesson in budgeting and the value of money.
I'm aware some people might disagree with these suggestions, which is fair enough.