When I received my latest (and hopefully last) speeding fine the vehicle registration on the paperwork was wrong, showing an 'F' instead of an 'E'. I paid the fine with no quibbles but was curious how I would have stood regarding the wrong letter.
I went on PepiPoo and enquired if this was worth raising as a technicality, as the wrong letter was on the officers booking slip as well, so all of the paperwork carried the wrong letter. I should add that I was stopped at the scene so there was no denying that it was me in my vehicle.
I was advised that if it went to court, the court would overlook the wrong letter as a slight admin error, calling it the 'slip rule'.
Surely in this case your wife made a slight admin error, so she should be able to use the 'slip rule' if it goes any further. After all, if it's good enough for the courts to use that as an excuse then surely your wife can use it in reverse.
The fact is, you paid for a space and can prove it in court so what more do they want. This is all an admin bullshit exercise on their part. What would their claim be?