Thanks for this interesting report. Have quickly scanned it and even though it has none of the info I was chasing it is very informative even though its 4 years old. I am going to see if I can find the latest report.
I can see how an idea of visitor numbers are more easily calculated for Hadrians Wall, given that many walkers buy the passport. (not necessarily accurate but a guide)
The details from Forest View are valuable also as that data helps others decide whether it is commercially viable to offer accomodation to walkers in areas where it has disappeared, or become scarce.
Airbnb are an unreliable planning source due to the ease with which bookings are cancelled, lack of insurance and in many cases just outright scans, and that last is from personal experience. They have just removed hundreds of scam sites from London, although I had a great genuine one recently in Dufton which is not currently advertised.