A court can't convict someone of an offence unless the prosecution have shown that there can be no reasonable doubt as to the person's guilt.
If the magistrates think that it's 'quite likely' that the woman was drink-driving, they must acquit her.
If they think it's 'extremely likely', they must acquit her.
If they think it's 'almost certain', they must acquit her.
They can only convict her if they are wholly convinced, beyond reasonable doubt, that she's guilty.
So Mrs Alko will simply try the ploy of saying "I was really shaken up by the crash, so I went home and had a few stiff drinks to steady my nerves. I'd not touched a drop before I got into the car".
The prosecution can't use your statement that the woman smelt of alcohol (as to do so would be to introduce 'hearsay evidence') unless you appear in court yourself, so that your testimony may be cross-examined. (Even so, the woman could suggest that you were mistaken or that she'd recently broken a bottle of gin amongst her shopping in the car, and that was what you smelt).
Courts are, of course, wise to such tactics but they still have to apply the rule that they can't convict someone if their defence team has shown that there's reasonable doubt.
Chris