TAMLYN I don't know, to me it looks like a pet form (deminutive) of a name starting with Tam- like Tamara or Tamsin.
According to the Oxford Dictionary of Surnames, Canham is from Cavenham (Suffolk). This again was called Kanauaham in 1086 and Cauenham in 1198. It means "Homestead or enclosure of a man called Cafna", which is said to be an Old English personal name. (This is taken from the Oxford Dictionary of Place-names)