That is the right family: they feature only in the 1841-61 census. Confusingly, they are shown as:

born in county in 1841;
he, ?? Essex (is there some other info. here?) and she Kingston on Themes (sic) in 1851;
both as Dedfort / De[lfort] / Deshfort, Hereforshire in 1861

I was putting forward a potential "solution" to tie Essex and "herefordshire" / "hertfordshire" together. As it stands, the information does not fit. However, assuming Herefordshire IS correct, I still cannot find a possible location there (no parish I can find).

I am trying to locate their place of birth so as to follow up this line (please ignore Sawbridgeworth!). Can you help?

(PS: the info. I have comes from transcribed census information.)