http://members.pcug.org.au/~ronwells/460-9.htm

http://fmg.ac/Projects/MedLands/NORMAN%20NOBILITY.htm#_Toc172613568

http://homepage.mac.com/james_keller/WC55/WC55_005.HTML

So, apparently it goes like this:

THURSTAN de Bastembourg

-son, Hugh (I) de Montfort

-grandson, Hugh (II) de Montfort (fought at Hastings, 1066, accompanied Conqueror to England and made Constable of England, retired 1088, became a monk, but not before fathering

-greart grandaughter, ALICE de Montfort-sur-Risle. She married GILBERT de GANT, and their son

- Hugo (IV) adopted the name De Montfort.

Not sure why Hugo IV jumps straight back to Simon, who as yet I have not discovered a connection to.