Private driveway legality?

There is an elderly lady who lives in the next building to me who has a driveway that is never used though she does not park in front of it she insists that no-one else does. the problem is that the street is mainly flats and cottage flats so there are a lot of people parking outside on what is quite a busy road. she has complained to me on several occasions even if i am miles away from her driveway and even sometimes when there is a car between my car and her drive and she is parked at the other side. i have three kids (10,3 and 1) so i need to park close to try and get them all in the flat safely. when she complains she can be quite rude and threatens to go to the council what i want to know is does she have any actual legal right as it seems like common sense that if she is not using her driveway that she would park in the space in front instead of effectively taking up two spaces.