Retention limits for seized accounting records clarified; transfer to competent assessing officer and right to obtain copies preserved. Clause 251 governs handling of books, documents and electronic media seized or requisitioned under clauses 247-248: where the seizing officer lacks jurisdiction the material must be handed to the Assessing Officer who then exercises the clause's powers; the entitled person may apply to make copies or extracts in the presence of an authorised official; retention beyond the ordinary statutory period requires written reasons and approving authority consent which is subject to Board review following an opportunity to be heard.