Many thanks to those who looked up the 1841 and 1851 censuses. None of the ones listed in 1841 seem to be the right person. But it is possible that "William Heslington occupier of Whetley Fold" in the census district of Manningham might be one of those listed in 1851. Is it possible to see who was living at Whetley Fold, or where it was in the district of Manningham in 1841? William could have rented the property and could have moved. Mary Tetley (whose death certificate started this search) was not buried with the rest of her family in the Baptist cemetery in Allerton but her son was brought up by her oldest brother in Heaton. She may have worked for the Heslingtons. She died of TB. All this is guessing the story. I have made printouts of all the materials sent to me to file as I go on searching. So the labour of those who "looked up" was not in vain. Thanks again. Helena - Canada