In the case of land specified in Schedule 4 (acquisition of new rights only) the Authority’s powers of compulsory acquisition under article 27 (power to acquire land) and article 30 (power to acquire new rights) are limited to the acquisition of such easements or other new rights in the land as it may require for the purposes of exercising the powers conferred by article 19 (attachment of equipment to buildings) and using and maintaining any apparatus affixed in the exercise of those powers.