INCORRECT  REGISTRATION NUMBER : ONE POSSIBLE  LINE OF DEFENCE ?

Motorists in their thousands get isued PCNs by these morally bankrupt private car carking companies. Why motorists need to enter car registration numbers is one question that needs to be asked ,  along with why they have to predict the period time they intend to stay. Having a barrier on entry which issues a ticket..... to be later entered into a machine prior to exit to determine payment avoids ( a) any need to submit car registration details and (b) any need to make an overpayment. But hey..... all this would severely undermine two very lucrative income streams.
Firstly,  motorists find it difficult to predict the time needed to park up so over-estimates and over-payments are the norm. Overstayers of course are warmly welcomed by these money grabbing scammers. Moreover incorrect registration number details are also commonplace with poor unfortunate victims being hammered , even though companies incur no actual loss whatsoever when tickets have been paid for in full..... and in good faith.
Innocent  and honestmistakes are made but no mercy is ever shown. Matching car registrations on the AVRC photos to whatever details have been keyed in offers no problems to these theiving rogue outfits to make a match. They know that motorists have paid for their parking spaces ,  but tariff revenue is not sufficient to satisfy their greed. They want to bleed motorists dry.
No sympathy, understanding or respect is ever shown to motorists who have made errors keying in their registration numbers irrespective of legitimate reasons as to why :
    - poor vision 
    - small lettering on key pad buttons
    - poor memory
    - key pads placed positioned so low down , users with bad backs cannot reach or read
    - arthritic, weak, shakey fingers
    - big bulky fingers unable to depress the right button from those in a tightly packed cluster
    - easily confused elderly drivers
    - keys which are faulty or non-working
    - keys which are hard to depress fully or are too sensitive ( double clicking )
    - drivers suffering from autism 
    - drivers who are dyslexic
    - hard to distinguish letters/numbers on the buttons ( such as zeros and O's , Q's and O's,
      B's and 8's , ones and I's , 5's and S's.......and so on 
Oh yes....these innocent and honest mistakes will never be accepted as legitimate excuses , because these evil companies have nothing but contempt for their victims..... being hellbent on making obscene profits from even the most weak and vulnerable motorists .
Therefore , it is my contention that this alleged violation brings about no loss or damage whatsover to the company , which means in effect the charge is a manifestly unreasonable penalty, unenforceable in a court of law. But the line of defence which does need to be researched and/or explored goes along the following lines :

Fact : the car parking ticket machine has been establish in law as  " the offer "
Fact : the offer comes with  "a pre-condition  " that the correct registration number must be entered into the machine prior to paying
Fact : by inadvertantly failing to meet this pre-condition , the offeree is making a term of his own 
Fact : by placing a variation on the car registration details , the purported acceptance has become by default  " a conditional acceptance "
Fact : a conditional acceptance is nothing more than  " a counter-offer " ( which the machine will not reject since it is programmed never to question or query the data input  )  
Fact : so when the machine accepts the information submitted along with the payment , acceptance of the counter-offer now takes place when the ticket is duly issued
Conclusion:  this of course makes the ticket valid

In other words... this scenario is the parking equivalent  of   " the battle of the forms ". So please add this line of defence to any others you may want to use in order to avoid being fleeced by these highway robbers. Your best bet is to take note of many excellent template defences available on tthe internet , details of which might well apply to your situation. Don't go to court relying on a single defence. Hit the bastards with everything, you've got....... including the defence above.