(1) In this section -

‘relevant statement’ and ‘return’ have the same meaning, respectively, as in section 152;

‘repayment’ means a repayment of stamp duty including any -

(a) interest charged,

(b) surcharge imposed, or

(c) penalty incurred,

in relation to stamp duty under any provision of this Act;

‘valid claim’ shall be construed in accordance with subsection (3).

(2) The Commissioners shall not make a repayment to a person unless -

(a) such repayment is provided for by this Act,

(b) a valid claim has been made to them for that purpose, and

(c) without prejudice to any other provision of this Act containing a shorter time limit for the making of a claim for repayment, the valid claim concerned has been made within the period of 4 years from, as the case may be -