Joan Skelton wife of Sir Robert Roos of Gedney is mentioned as the dau. of Alice Ireby & her 1st husband Geoffrey Tilliol, MP in History of Parliament.
See the "About" sections of Joan Skelton & Sir John de Skelton or http://www.historyofparliamentonline.org/volume/1386-1421/member/ti... & http://www.historyofparliamentonline.org/volume/1386-1421/member/sk...
Should her parentage be changed?
Yes.
The History of Parliament biographer shows that he knows that Joan and Katherine have been ascribed by genealogists (originally Wrottesley) to John Skelton rather Geoffrey Tilliol. It is also clear that they were sisters. Since Katherine was married to John's son, Robert, she can't have been his daughter.
Mark