ahh great, thanks for the advice guys/girls. so there's definitely no chance that they can sue me or send me to court? ill just receive a few nasty letters?

I am a student and I have recently been parking my car in my mates flat, as he was provided with a car parking space in his contract (forms part of the building, he was given a key fob when he moved in which opens the gate into it). He was given a numbered space but of the few times ive parked there, someone has been parked in it, so ive just parked somewhere else as the car park is always half empty. However last week I came to my car to find a PCN from VCS parking control saying I had £85 to pay within 14 days, and it would be reduced to £65 if i paid within 7 days. On closer inspection there are three rather official looking a4 signs stuck around the car park (picture at bottom) saying "permit holders only" and most cars seem to be displaying a permit (sneaky picture at bottom). i've since spoken to my friend about it, and annoyingly he cant find his contract- but he is certain there was no mention of a permit whatsoever and that it clearly stated in his contract he had a parking space. should i argue to vcs that i rent a space and someone had parked in it, and in my contract there had been no mention of a permit required? i'm new to this forum and have been looking at all the very useful information on here, i feel inclined to ignore it until they send me a letter and then reply asking for proof of who the driver was, but my car is registered to my parents address and i know that my mum is going to go crazy when bailiff notices start coming through the door. what should i do? do i have any grounds to not pay when there was clear signage, i was just stupid enough not to read it; but my friend is paying for a space as part of his rent and someone had taken his allocated space? help! notice the "VCS" printed bit on the permit?