@Islamisright
I'm of several minds about the burka vs a niqab vs a hijab.
Maybe a system of gradation depending on how mischievous a female is normally or how attractive she is would be good, perhaps? I'm not suggesting that any of this is enforceable-- think of it as helpful suggestions or guidelines.
No covering her up though, that is haram.
@Islamisright @DoubleD I think. If she is single she can wear what she wants.
But If she wants to be in relationship there is no need for her to act like she is single and attract other men. For that reason she should wear modest clothes.