Its a shame nobody submitted the schoolroom a few years back.
"The Lake District" would get my vote, stunning "natural" beauty. Also the "Slate Industry of North Wales" on the proviso that Dinorwig quarries remain open for climbing.
I just think on a world scale its not that amazing, you only have to travel a couple of hundred miles north to Scotland to find 'better' if it is possible to quantify prettyness in this way
Are you telling me it isn't already a UWHS?