I received a parking charge dated 21 April 2018,   I am just wondering do I really have to pay this and is there anything I can write back to refuted their claim,   it seems like a bit of a joke as their is a sign on a gate which has been blocked up by a 2 tonne concrete boulder saying no parking as access is required at all times, or something along those lines...   should I take this seriously?   Scan attached.   Best Wishes   Billy