This is Matilda/Maud de Kevelioc. Be sure to read the About Me. If Mabel is linked to this, it's incorrect. I'll do some work on this right now.
As for the Mabel who was married to William'd'Aubigny, everyone *please* be aware that there is a very confusing situation of two separate men named William d'Aubigny who were married to two Bigod sisters, Maud and Cecily. There are two lines of d'Aubigny and they actually seem to not be related. One are the d'Aubigny family who were Lords of Belvoir and the other the D'Aubigny family Lords of Arundel. William "Pincerna" d'Aubigny, Lord of Buckenham (Arundel line) married Maud Bigod, while William "Brito" d'Aubigny, Lord of Belvoir, married Cecily Bigod. These were daughters of Roger Bigod and Adeliza de Toeni.
Thanks! I pulled out lots of hairs a few months ago trying to sort out these different threads of d'Aubigny's and related families (of course now, there are lots of new tangles!).