Provided also, and be it enacted, That nothing in this Act contained (hall extend to empower or enable the laid Commissioners of His Majesty's Woods, Forests, and Land Revenues, or the Surveyor General of His Majesty's Woods and Forests for the Time being, to grant in Exchange or make Sale of any Land within any of the said Forests, in such Manner as to prevent any Person or Persons having Right of Common on such Forests from having Access to such Forests for the Purpose of enjoying such Right of Common, as effectually and conveniently as he or they now has or have, or otherwise might have had, or to prevent any Person or Persons from having Access from the said Forests to any Lands belonging to him or them, lying adjacent or contiguous to the said Forests, as fully as he or they now has or have or otherwise might have had.