I have found him in Medlands now and this seems to corroborate what you have said Martin:
son of Robert d'Ivry and Albreda (parentage unknown she married secondly Albert de Cravent)
Roger was brother o fRobert and Hughes D'Ivry
Roger m Adeline and according to Medlands had one child Adelise however this profile's About me claims he also had sons, Roger, Hughe and Godfrey.