really?

[Grahamm]

I will refer you to rule 243 of the highway code. This is something you can get a parking ticket for (though most plod and wardens don't bother)

Ok, good point. It's not something I normally worry about, being on a bike

So, yes, it's possible that that was what the ticket was for, but it's still an odd co-incidence that it happened on the day when the permit wasn't visible due to snow.