The Cities of the Plain were Sodom and Gomorrah where Lot's wife got turned into a pillar of salt - Sudheim in Shetland has been anglicized as Sodom
Why Pope John XXII I wonder? The famous one was Pope John XXIII. But anyway, did you see my idea for this one -Holm of Papa? Not totally convincing, but it's at least a possible.
Nearer Skye is enough to make me jealous! There's not much in the way of mountains or sea lochs in Milton Keynes. I only just qualify as a highlander. Comrie sits on the boundary fault but it's a long time since I lived far enough North to pop "home" for the odd weekend. Maybe this Summer!