Why did Joseph Hamlet change his name

During the course of his life between 1850 and 1933, Joseph Hamlet changed his name  several times

1845 Samuel’s marriage certificate    Hamblet
1850 Joseph’s birth certificate                 Hamlet
1851 Census                                           Hamlett
1861 Census                                           Amphlett
1862 Samuel’s death certificate              Hamlet
1862 Birmingham Daily Post                  Amblett
1871 Census                                          Hamlet

1873 Joseph’s marriage certificate        Hamlinton

1881 Census                                          Hamilton

1887 Walter’s birth certificate                Hambilton

1891 Census                                         Hamblington

1901 Census                                         Hamlinton

1911 Walter’s marriage certificate         Hamilton

1911 Census                                         Hamilton
1933 Joseph's death certificate             Hamilton

 

According to my father, my grandfather Walter, Joseph's son, was always very insistent that despite the fact that some people used variations, the family name was Hamilton. This wasn't true, and indeed Walter's own birth certificate Hambilton. Indeed Joseph's own marriage certificate to Sarah Emily Mills has Hamilton crossed out and replaced by Hamlinton. We had assumed that the variations were the result of sloppy enumerators, but there is one further twist. Joseph's  birth certificate gives his name as Joseph; his marriage certificate gives his name as Joseph, Walter's birth certificate gives his name as Joseph, and his death certificate gives his name as Joseph. My father who is named after him always refers to him as "Old Joe". But on Walter's marriage certificate his name is given as Thomas Joseph. Why? Is there some dark secret that made Joseph change his name when he moved from Tipton to West Bromwich?

 

I think that we who were born Hamiltons are unlikely to want to change back to Hamlet, but I did waste a lot of time in my youth supporting Hamilton Academicals unnecessarily.