I also have the Thomas allen/Sarah Grande family.My ancestor is their daughter Sarah Allen who married Jeremiah Knowlton in 1717.
For Thomas Allen (b. 1690), I have his parents as Benjamin Allen (b. 30 Jan 1662) and Frances Rice.Benjamin's parents were John Allen (b. ca 1631)and Sarah.John's parents were Walter Allen and Rebecca.
I have not found anything on Sarah Grande's parentage or ancestry.Have you?