While merging some new data from a relative with info I already had, I saw that for one spouse he showed the name Purkis for a maiden name, while I had Whybro, although the given name was identical. Checking the index for the marriage, which was in 1953 at Southend, I found that it shows "Purkis or Whybro" for the surname.
There were several in the same index page that were similar - but why? Surely the registrant would ask to see evidence of the legal surname?