Looking at FreeBMD there is a marriage registered between Elizabeth Powis and Thomas Powell in the June quarter of 1867 at Weobly which is located around the border of Worcestershire and Herefordshire. Not quite Wales but near. The GRO ref if you want to order the cert is 1867 June quarter Weobly volume 6a page 889. I am generally interested in the Powis families as I am stuck with my own research c 1800 and am convinced that they originated in Herefordshire or Shropshire. So I would be interested in your Powis family tree in case there is a connection.