Making assumptions, even quite logical ones, can give you problems. If you hit a dead end, go back to square one and double-check EVERY assumption you've made. You might be very surprised - I was!
It turns out that I misunderstood the word "hamlet". In the context I found it, it didn't mean a tiny village sort of thing. Apparently a "hamlet" was also a subdivison of a parish, and could be a huge area! See this Wikipedia article
http://en.wikipedia.org/wiki/Ystradyfodwg for the moment of enlightenment!
Keep checking those assumptions!
Pete
