Euro Parking Services PCN NTK

[FearonH]

I recently received a PCN from Euro Parking Services via post. I did not see the signage but i know it is there now that i've checked. Is it possible for me to avoid payment? The 14 days already started 3 days before it arrived, and i see no way of proving that. More importantly, I'm wondering if there's any proof that the letter was posted through my door, can i claim that i haven't received it and avoid the penalty, seeing as it's their responsibility to ensure that the vehicle keeper (me) has received the notice.