Really dont want to fall out with an elderly neighbour but maybe my wife has a point?
Your neighbour has a right to do whatever she likes in her own driveway - your vehicle shouldn't have been even partly on her property.
Those are the bald facts; how you deal with the relationship side of it is up to you, but remember that you told her to get a price. That was tantamount to an admission of culpability. Your neighbour has simply done what you asked her to do.