Wow, what a speedy response! Thank you, Cat.
These are certainly the right people, but I would still like the full PR entry. I've not been able to establish who Elizabeth's parents were (though speculate they were William Garrett and Mary Reading of Well Farm, Dagnell in the parish of Edlesborough and thus her sisters were Sophia, Ruth and Maria, all born at Dagnall), so any clues may be helpful. I'd found Elizabeth in 1851 and 1861 census only (she died in 1870) and these show her birthplace only as Bucks and England respectively. There were also Garretts of the same family as William living at Hudnall in the parish of Edlesborough. Plenty of scope for jumpng to the wrong conclusion!