25A person who in furnishing particulars under this Part of this Schedule wilfully or negligently furnishes particulars that are false in any material respect is liable to a penalty not exceeding the aggregate of £300 and twice the amount by which the stamp duty chargeable exceeds that paid.
26An instrument in respect of which duty is chargeable under paragraph 2 of this Schedule which—
(a)has been stamped ad valorem, or
(b)has been stamped with a stamp indicating that it is chargeable with a fixed duty under paragraph 6 (instrument in substitution for one stamped ad valorem) and has been stamped under that paragraph,
shall be treated as duly stamped for all purposes other than paragraph 25.