10SIf, in a case falling within paragraph 9, it is subsequently shown—
(a)that the land, or the claimant’s interest in it, was subject to an incumbrance which was not disclosed in the particulars of his claim, and
(b)that by reason of that incumbrance the compensation paid exceeded the compensation to which the claimant was entitled in respect of that interest,
the acquiring authority may recover the amount of the excess from the claimant.