One street on the estate is named after the farm that used to be here and the others are named after reservoirs and places around the Elan Valley (eg Rhayader, Tregaron, Claerwen)
That would be because the Elan Valley was turned into a load of reservoirs to provide water for Birmingham, and the waterworks that processes it into council pop is literally across a field from us, so there is more logic to it than it just sounding nice.
I reckon places in the Peak District and Lake District must be the most common theme for housing estates across the country.