I worked on a similar project with the Wilderness Society mapping remaining 'wild places' in the CONUS - the model was designed to be scale-relative, so depending on what scale you mapped at, the wildness was relative. Which makes sense, as I've been to a 'canyon' just off the busy streets of Los Angeles and it was silent and tranquil - no sight or sound of urban noise. So there are places just outside Liverpool or London that would also make ideal retreats. That said, I think the terminology used in the article plus the map's scale of analysis can be misleading and coarse "There are only a few really large areas of tranquillity left in England. " (i.e. tranquility is relative). Plus, mapping buffered roads as a surrogate for (you name it) can overestimate, especially when mapping 'tranquility' - if they had traffic volume (AAT) data - that would be better. Overall - glad to see the application to GIS in bringing attention to England's remaining open spaces. Another thing to consider (stop me now) is the cultural differences - in Italy, tranquility may be found in the regional park for most people - so an important pre-step is determining what defines 'tranquilty' and 'wildness'.