Opening and Working Enquiries: Method of obtaining information
You may sometimes consider that you can more conveniently obtain the information you need at a meeting with the customer(s) or over the telephone. If you are carrying out a full enquiry, you are likely to need a meeting with the customer(s) at some point. You should use your judgement in deciding whether to obtain some or all of the information before the meeting, or to ask for the customer(s) to make it available to you at the meeting. You should only obtain the information over the telephone if the information you need is fairly limited and straightforward - this approach will be particularly suited to discrepancy enquiries and is not appropriate to full enquiries.
Whatever approach you adopt, remember that you must always issue a formal written notice of the enquiry to the customer (or both of the customers) at the outset of the enquiry. And if you are unable to obtain the information over the telephone or in person, you will have to follow up your original request in writing. In these circumstances you should always write to the customer(s) informally requesting the information, and only issue a formal information notice if the information is not produced by the time specified.