Where in the World Are We?

Some clues:

Reservoirs, so there must be plenty of rain here.

Lots and lots of sheep. Goodness, I thought there were a lot of sheep in Oxfordshire! {g}
Mountains, snow-capped in April.
They speak another language here.

Hang on a minute! Bison? Are we in North Dakota? No.
Who's this handsome chap?
There's plenty of wind here.

Yes, we are in Welsh Wales!