Although he is directly concerned with the Cornish representatives of the Symons family, his comments on the origin of the family name and its derivitives are very interesting!
"Lots of variants exist but, to give just a few, here they are; Symons, Simons, Simmons, Symmons, Symonds, Simonds, Simmons, Symmonds. Quite a few of these appear in this family history, sometimes in the same family, perhaps indicating that the parish recorder was changed during the expansion of a particular family. Although our story is about Cornwall and Cornish people, it may seem awkward to have to admit that Symonds is not a name with its origin in Cornwall. It is quite probably Norman and came to England with William the Conqueror, at least in many cases."
Thought you might find that interesting. Best, Bev symons