I'd be expecting an offer of around 72k if someone said 'not a million miles away' from 75k.
But I wouldn't accept it.
One of the reasons the gender pay gap exists is because women tend to be more reluctant to enter into salary negotiations than men. If we accept less money, we get offered less money, and so the cycle continues. The more women who know their worth, ask for what they're worth, and stand their ground until they get it, the better for all of us.
If you want 75k, and can justify 75k, then refuse to entertain any discussion of anything less. Why should you? And if a company really wants to lose an excellent candidate over a couple of grand, then they're not the sort of company I'd want to work for.
Honestly, if I were you, I'd go back to them and say you consider 75k to be the appropriate salary for the role due to the following reasons (i.e. your skills, experience etc.) As such you won't be willing to renegotiate and it's either 75k or you'll be going elsewhere. If they really want you, they'll find the extra couple of thousand.