St Thomas More's head is buried in the family vault of a side chapel of St Dunstan's Canterbury. The chapel was constructed by the Roper family. More's daughter (Margaret) had married into the Roper family and it's thought that she bribed a guard to retrieve More's head from the Tower of London after his execution there for treason.
When he was buried in the chapel, I'm not sure if the church was yet 'Anglican', as the church of england was still in the process of being formed out of the political turmoil of the time. The church is open to visitors and pilgrims, and they had some information about the history of the Roper chapel. It seems that they were only able to confirm that St Thomas More's had been buried there during an excavation in the late 1970's and the head was reburied there, along with the remains of his daughter, her husband and family.
On another note... did you know that both St Thomas More and St John Fisher are included in the Anglican lectionary (on 6th July)?