What's in a name?

Thomas Dykes was elected Master of the Charterhouse on 5 February 1833.  Or was it Thomas Dikes?
The family name appears clear in the transcriptions of the parish registers.  Both his baptism in January 1762 and his marriage to Mary Hey in 1789 have it with an "i", although the "y" variant of the name is generally more common.  Thomas's entry into Magdalen College, Cambridge, in June 1785 appears in Venn's Alumni Cantabrigienses as "Dikes or Dykes"; but Venn compiled his list years after Thomas's death, when confusion had set in.
The fact is that all his life Thomas insisted that his surname was Dikes.  Contemporary records have that spelling because that's how he wrote his own name, and there would have been no reason to disagree. Among other documents we have his signature on a warrant for the police to remove

inmate John Gill from the Charterhouse.  
Thomas was the leading Anglican evangelical in Hull, and people who have written about this aspect of his life in modern times, like Peter Stubley (A House Divided, pub Univ of Hull, 1995), draw on the documents of the time and use the "i" spelling.  

There are numerous mentions of Rev Dikes in the local papers of the time; they report on him as Vicar of St John's, and on his involvement in local good causes; they report his appointment as Master of the Charterhouse and print an obituary of him on his death.  Every single report has him as the Rev Thomas Dikes.  That was simply his name.

So why is there so much doubt about the issue that every reference to him today in the context of the Charterhouse calls him Dykes?
The clue appears in Dikes' will.  He makes his eldest son, also Thomas, his executor and refers to him as "my son Thomas Dikes (usually written by him Dykes)".  When the will was proved in December 1847 the official record refers to "the Oaths of Thomas Dikes otherwise Dykes and William Hey Dikes the sons the executors".  Clearly it was Thomas junior who had decided that the family name should correctly be Dykes and that his father had been wrong all his life (with his brother William apparently disagreeing).  It was presumably Thomas junior who registered his father's death - as Dykes - and who insisted that the memorial tablet in the Charterhouse chapel carry that version of the name.
Only two years after Thomas' death a book was published about him: Memoir of the Rev. Thomas Dykes, LL.B, incumbent of St. John's Church, Hull, with copious extracts from his correspondence, Rev. John King, (pub 1849, Seeleys, London).  King tackles the question of the spelling in a footnote: 
"It is right here to observe, that, during the whole of his life, Mr. Dykes spelt his name Dikes; but it was a corruption of the family name; and in a memorandum, found among his papers after his death, he directed that it should appear on his coffin with the y instead of the i.  This instruction was attended to, and the spirit of it is carried out in the Memoir now submitted to the reader."
This is hardly conclusive.  As we have seen, there is good reason (in the parish registers) to think that the "i" variant is not a corruption; and no source is given for the memorandum, which strikes me as highly dubious.
But the revision stuck.  He is Thomas Dykes on our roll of Masters, and one of the modern blocks of flats is labelled Dykes House.  It seems disrespectful to the man and his memory.