I've received a private parking charge notice (PCN) after waiting in my car for three minutes at a shopping centre loading bay. I did not leave the car at any time and stopped in order to pick up my 87 year old mother, who can't walk far. The demand is for £100, reduced to £60, for prompt payment. If I had parked the car the charge would have been £1.20 for two hours. I have been told that I should send the firm £5 as a settlement for the parking charge and postage costs. Will this work?