At present we have Elias Giffard +bef 1248 with two daughters, Maud and Matilda, one of whom marries the other's grandson. As both women marry Godfreys and have sons Peter, the one surnamed Bolbec probably got confused with the other and became attached to the same parents. It's certain that Alice Bavent was Maud's granddaughter as per the ipm of her cousin of the half blood, John Giffard, taken in 1327 and that Matilda married the Godfrey who was sheriff of Wilts in 1258.
I'm suggesting amputating Maud from the Giffard family. Given the duplication of Godfreys and Peters, it's possible that there never were two Godfreys and Peters, but it's hard to say. In any case if both Godfreys married Mauds, the latter women could not have been sisters.
British history online has a Godfrey Scudamore "probably dead by 1190" succeeded by a Peter (son or other relation?) who was succeeded by a Godfrey (again no specified relationship) who held it to at least 1262. This would appear to be Matilda's Godfrey, but was he the same as the earlier Godfrey or a different one? Then there's a son Peter succeeding by 1267. But the succession was not necessarily a straightforward father to son to grandson one as the lands were forfeited, reallocated, and reinstated at various times so more data would be helpful to sort out the relationships.
p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px 'Lucida Grande'}
http://www.british-history.ac.uk/report.aspx?compid=16080