under Article 280, after the expiration of 42 days from the day on which it first came to the knowledge of the trustee that the property in question had been acquired by, or had devolved upon, the bankrupt;

under Article 281, after the expiration of 42 days from the day on which the property in question first came to the knowledge of the trustee.

anything which comes to the knowledge of the trustee is deemed in relation to any successor of his as trustee to have come to the knowledge of the successor at the same time; and

anything which comes (otherwise than under sub‐paragraph (a)) to the knowledge of a person before he is the trustee is deemed to come to his knowledge on his appointment taking effect or, in the case of the official receiver, on his becoming trustee.