In my job as a cleaner I spend time every day putting out warning signs about slippery surfaces. The location of this cache has no such sign, but it certainly is slippery!
The co-ordinates given are for the best and easiest place to enter the stream bed, and it can be approached from either side, via one of the other two waypoints given, each of which marks an access point into Ox Hey Wood. There are other access points, but you can follow a continuous path to the stream access from either of my recommended start points, though the paths may be a bit overgrown in places. Please keep your dog on a lead until in the woods if you choose the approach from Stubbins, because there are often cattle in the field. If you have a large dog, you will be better entering the woods at the foot of the hill as the stile isn't dog friendly. Then proceed to the southern access point.
Once at the stream, enter the bed and walk UPSTREAM. There are a few obstacles to climb over or around such as tree branches and rocks, so watch your step. Also, the water can be knee deep in places, so choose your footing carefully.
After a distance of 150ft or so, you will reach an obvious impasse, a green waterfall which looks as if it would be tricky to climb. DON'T go any further! You have reached the cache location, which is a rocky crevice on your right, about 3 feet up. (See spoiler pic) The container is a small plastic box with the usual log and swaps. Hope you have fun!