Legal Advice Needed..

[Cam]

Greetings,

Hoping some of the informed members around here might be able to help me out.

Last week I reversed into a motobike in a PRIVATE carpark at work. The bike was parked behind a carpark (that i was parked in), in the middle of a footpath, that runs paralell to a building. (does that make sense?)
My car was not reversed the whole way up to the "concrete block" so i was still well within my park. According to witnesses (and vid footage) i reversed into the bike, the tow ball tapped the bike and it fell over.

Now i had the wagon full of boxes and crap and with the radio and etc what not on i honestly didn't hear anything and i couldn't see the bike out my back window (i checked when i left in the afternoon), I got out of the car and walked in the opposite direction to my work so at the time was none the wiser, Until he confronted me after work and showed me ALOT of damage.

Now the owener of the bike works at a construction site next door to work. There are (and i have pics) 6 signs that state *NO CONSTRUCTION WORKER PARKING**. The closest some 3m from where his bike was

My Question is how liable am I considering he was parked on a footpath, while theoretically parked illegally on private property?

Thanks in advance!

Cam