The only baptism of a William Challis around the right time that I have found was at St Marylebone and the register shows his date of birth as being 25th January 1773. If this is the right William Challis then his age for the 1841 Census should have been 68 rounded down to 65 whereas the age shown was 60. Also his death in 1849 when he would have been 76 is not consistent with the age of 74 on the registration of his death or 75 in the cemetery records. However, the informant for the death registration was a 26-year-old servant rather than a relation so she may have had to guess!

The 1773 baptism registration shows the parents as William and Susanna and I have not found a plausible marriage for these people. There are marriages of a William to a Susanna in Cambridgeshire at somewhat later dates.