Just look on Google Maps for quarries near you then go check them out at weekend see if they are working or not and if they are accessible, I go on a few quarries I've found that way, one is still in operation but they never open Saturday or Sunday, one bonus is it's always changing, never had any trouble, it's in haslingden. Cowm is the only legal place round here, Lee mill is good as well, flappits in denholme is also really good but you will probably get moved off, I got moved off last time I went but after a couple of hours. I got stopped once by police off road on a local disused factory, because I had my van parked outside and wasn't really doing anything wrong, they just said crack on, stay off the roads and canals and if we see your van here again we will know it's you and just leave you alone, they had me tap a few walls then left.