BUT - and it's a giant 'but' - where are all these caves?
Let's go back to when there were perhaps fewer than half a million people living in what is now England. Wasn't there a massive cave shortage (as well as a shortage of 0% mortgages for young neanderthals et al) throughout the country?
Where were all these thousands of caves in Lincolnshire for example? Are we to assume that today's Lincolnshire, along with a score or two of other largely caveless counties, was unpopulated?
I would be hard pressed to find accommodation for more than a handful of speleos in my locality.
Even cave-filled Derbyshire could only have supported populations of a few hundred at best and few suggest that the Peak District was a major centre for such jolly folk.
I think that once again, historians 'have sold us a pup'.