Thank you Siani, I was aware of the pfmustoe site but unfortunately the Trows shown on it are mainly from the Kerry area.
Early in my research I thought my great, great, grandmother, Jane Trow, was shown on the site. Later after I obtained her marriage certificate, I discovered her father was Joseph, a butcher. Jane was born in the Berriew area and was married in Welshpool, which suggested her father lived there. A number of her children were also born in Berriew. However I have been unable to discover more about her, or her family.
Her family may well have come from across the border in Shropshire, but for all that they remain a mystery.
Thanks again for your interest, Dave