A lot of the families with surname Dunn residing in Radnorshire, Presteigne, Herefordshire, Staffordshire & Shropshire have been mistranscribed at the online major sites - I found mine in various census returns residing at the same location named as Dam, Dun, Dum, Don and Din in places called Pressign, Rads with Lingen listed as being in all of the counties/areas on different census returns
I have the names Edward and Emma in my tree but latter born 1840 in Lingen, Herefordshire. Various family members moved between census returns, some to Staffordshire so worth looking in surrounding counties as this may be the case with your ancestors.
We 'may' have a distant connection although I have checked my tree and am unable to find one to my Edwards or Emma's, however, the names appear to be common in our branch and there are several siblings and aunts/uncles that I have not researched who may belong to you!