The Complete Peerage, 2nd ed., Volume 10, p. 331-332 has William Pecche, and his first wife Alfwen, who is alive in 1088 when they receive a grant of Over, Cambridgeshire. No family is assigned to Alfwen, and given her name seems to be Saxon rather than Norman, I would go with Unknown rather than de Normandy as the name to use in Wikitree.
Feudal Cambridgeshire, p. 93 by William Farrer, also quotes the same grant in 1088 but calls it Ofra rather than Over
The Complete Peerage adds that William Pecche married secondly Isilia, probably daughter and heir of Hervey de Bourges,and their son Hamon de Pecche was the eventual heir of his father's lands. There were two other possible sons Simon and Ralph that were older and perhaps sons of Alfwen but both seemed to have died without heirs.
There is no mention of a son of William and Alfwen (or William and Isilia) named William, in The Complete Peerage, or in Feudal Cambridgeshire or in the Medieval Lands database.
The Clopton family (rootsweb.ancestry link above) seems to use the Visitation of Suffolk 1561 as its source for the early Clopton family, but that seems to make no link between the first William Clopton and William Pecche. They have obviously made the assumption that the Clopton name came from the manor of Clopton in Suffolk, held by William Pecche but this may not be correct. I think the 'son' William should be disconnected or at least marked as Uncertain.
I do have some hesitation over what appears to be a long generation between William de Pecche and his son Hamon, given that William is mentioned in the Domesday Book of 1086 and Hamon was still living in 1178, but died before 1185. However I guess William could still have been relatively young in 1086 (maybe 30) and Hamon as a younger son by a second wife, not born until 1095-1100?