Darwin, you might be interested in this article from the...

Darwin,   you might be interested in this article from the Marcellus titled, "Does Thickness of Shale Predict Production" https://www.fractracker.org/2011/08/does-thickness-of-shale-predict-production/

They didn't find good correlation b/w shale thickness and production.  

I haven't heard of anyone drilling in a pay zone that is as thick as that of the Bowland.  That said, I don't know how much of the 1 mile of shale in the Bowland would be classified as good pay.  My guess is that Cuadrilla has views on this.  Regardless, the ability to extend multiple laterals at different depths from the same site or even the same borehole improves economics while minimizing land use.  In other words, it make a huge impact on the amount of energy produced per unit of land - which makes shale gas look much better than most alternative forms of energy.