There is definitely a problem with the merge which appears to have already taken place. Hopefully someone will be able to fix that.
The Complete Peerage, vol. 8, pp. 577-86 refers to the family throughout as Mautravers, and I think when an issue like this has come up before, we have gone with the name as in The Complete Peerage. The volume is available in FamilySearch.
There are a couple of other issues with the profile. He was summoned to Parliament by writ and is held to have become Lord Mautravers, (see Complete Peerage, p. 583) not Lord of Mautravers. He also probably doesn't need First or 1st as he was essentially the only Baron or Lord Mautravers.
The John Mautravers of Hooke and Crowell, is definitely not his son by Agnes Bereford. The inquisition post mortem taken after her death, states several times that there were no issue from this marriage. See no. 180 with inquisitions under Gloucester, Somerset, Wiltshire.