So, if the driver at the time is unknown [can't recollect). what happens if it's, say, a company pool car? The "company" doesn't have a driving license to slap 6 points on. So do they get walloped with a huge fine for failing to keep records on who the car was signed out to? Seem to remember...
First piece of advice - SLOW DOWN ! [both of you]
As you've described the prosecution as "Failure of keeper to name the driver" and professed to genuinely not knowing who was driving, your wife is guilty as she's not named the driver as required by the law. So, I don't think they're ignored...