(2) If, in the case of any claim under section 23, sub- section (1), thirdly, by a person interested, on account of the severing of the land to be acquired from his other land, the[ appropriate Government] is of opinion that the claim is unreasonable or excessive, it may, at any time before the Collector has made his award, order the acquisition of the whole of the land of which the land first sought to be acquired forms a part.