Trust hmrc registration

A deed of variation in an intestate estate was created all assets to spouse with the deceased’s person ‘s share of property on trust for a minor child in 2012 with right of occupation to husband on her share of property. Would this be a bereaved minor trust? If so does it need to be registered at HMRC? The child is now 18 and therefore inherits his mother’s share? If a trust does it now simply come to an end?