.......... doesn't really enter into the original question of the legality of the ticket.
I'd pay up & take the hit......
As I said earlier, the ticket may well be questionable as far as a ticket goes but I know from experience that if the son of the OP decides to not pay then a fixed penalty ticket of a different sort - but with the same penalty - is generated on behalf of the Court after the 28 day payment window.
Likewise, I have seen errors on said tickets that went all the way to trial in a Court in front of the great and the good and all that was done when the error was finally offerred up as a get out of jail card by the defendant, the prosecutor simply took the ticket/summons/copy complaint and corrected the date/address/reg number/whatever and simply burst the bubble of the defendant in front of the Court.
I know how I would deal with it but its the sons call, ultimately. 
I once got a parking ticket , for being on double yellows a tad longer than allowed, that had the reg number slightly incorrect. I never paid it....since that reg number wasnt my car

However that wouldnt work now, since they take piccies of the reg number

Oh and i got a no seatbelt ticket once upon a time, before i was a cabby......£10 fine then.
And for some reason, since driving 9 seaters, i never put on my seatbelt and never had my collar felt for it......im not totally sure all pc's understand the law concerning seatbelts and private hire/taxi's, so just dont bother to pull me in case their wrong
