Private parking tickets are actually invoices which are issued under contract law. Legally this is known as a contractual penalty and is unenforceable.
They (NHS) are only allowed to claim for actual losses suffered. In the OP`s situation as he has parked over two bays he has breached the terms of the parking rules & regs on that particular property. They can't enforce a charge for you breaching this agreement only a reasonable charge for any losses incurred. Ignore it
Thanks Rob

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well i am just glad the person issuing the ticket was not there........we all know how Del gets with parking wardens ...mind you not far to go to the hospital
I'm fine with them, honest

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It was just parked a bit iffy, I'll fully admit to parking badly, however the back wheel was well in my space, the front on the line. Annoyingly I went out there to put more money in the car park (still had 10 minutes remaining), and then found the ticket, unbelievable.