29. A creditor shall not vote in respect of a debt on, or secured by, a current bill of exchange or promissory note, unless the creditor is willing—
(a)to treat the liability to them on the bill or note of every person who is liable on it antecedently to the company, and against whom a bankruptcy order has not been made (or, in the case of a company, which has not gone into liquidation), as a security in their hands; and
(b)to estimate the value of the security and, for the purpose of their entitlement to vote (but not for dividend), to deduct it from their claim.