Peter, I looked up Henry Norwood, and he lived in the thick of very interesting times! I'm descended from the "other side," Samuel Mathews (Sr. and Jr.), who were leaders in the Commonwealth faction that came to power after Virginia submitted to Parliament and Norwood returned to England.
Anyway, regarding various Magna Carta descents for Henry Norwood, I'll suggest, first of all: do a google search with the words Henry Norwood Magna Carta Ancestry. That should bring up a link to Douglas Richardson's treatment of Henry Norwood in "Magna Carta Ancestry," which is freely available online. (Selected snippets are available, including Norwood's ancestry going back to Bohun.)
If you go there you will find, if you scroll up a bit, that Richardson includes a lineage from Norwood's mother to Magna Carta baron William Malet. But that lineage isn't available in the online snippets from Richardson's book, and there are doubtless many other lineages in "Magna Carta Ancestry" that have been thoroughly researched. (And if you wanted to improve the profiles for those lineages, they could eventually be badged like the well-established and Magna-Carta-Project-approved Norwood lineage to Bohun.) (And keep in mind, Richardson's more recent "Royal Ancestry" sometimes includes corrections and additional information not contained in "Magna Carta Ancestry.")
Richardson does NOT include lineages through the mother of Henry Norwood's grandfather William Norwood. Maybe he felt unsure about that Throckmorton ancestry; see this old SGM post: http://webcache.googleusercontent.com/search?q=cache:http://archiver.rootsweb.ancestry.com/th/read/GEN-MEDIEVAL/2013-08/1376548718
I can't access the responses to that post, but maybe that line has been firmed up since then; there's something for you to check further if you have the time and inclination. Right now the Throckmorton connection is shown on wikitree as a certain lineage, and there seem to be Magna Carta lines back there that Richardson didn't include. (?!?!)