Park in the east car park, take the path to the right of the car park, follow the path all the way, you will get to a point where you can either go left or straight forward, keep going straight and walk up the hill, you will see the quarry, then to get into the quarry you take the path to the left all the way around and jump the wire fence, thats how me and my friends found it, if you need more help just go on to google earth thats what we done mate!
It's fenced off now since a lad died in it last year but if you follow what the above comment says, it's only a fence blocking the quarry. Went today, its quality👍