Pickering trout lakes is purely a 'fun' fishery, it's the place i took both my sons and daughter when they showed an interest....Great day out for the kids, took them on the steam train where it goes up to Goathland (heartbeat is filmed there), then back down, let them feed the trout at the farm, and then..fill yer boots....fish a cast...pay by the weight.
As i said, good for getting young ones into fishing by guaranteed catching fish to keep them interested.
Not too sure about the closest lake, but there are quite a few fisheries in north yorks, river fishing may actually be closer
Yorkshire Fly Fishing, a guide to fly fishing for trout in yorkshire
Good luck