As long as you obtain a separate authorization from that obtained for the credit report fee (after the LE has be received by the consumer and the consumer has indicated their intent to proceed) and it is clearly documented, the authorization can be either verbal or written.
From the preamble of the Intergrated Disclosure Ruels, page 305-306: The Bureau believes that the term “separate authorization,” as used in the comment, clearly means a new authorization, whether verbal or written, from the consumer for the creditor to charge new fees. The Bureau believes that an expression of a consumer’s intent to proceed with a transaction is not the same as an authorization to the creditor to charge additional fees.