I'm an American just beginning to work on some Welsh ancestors. I have no "feel" for what constituted being poor versus being well off in terms of net worth, now or in the past. If someone living in Wales left an estate of £225 in 1925, can someone please tell me roughly where on the economic ladder they would have been viewed?

That would have been roughly US$1100 at the time, so they would definitely not have been considered poor in the U.S.