An information notice must state the time by which the information required is to be provided. The statutory provisions do not say what is a reasonable time to allow but it is normally taken by HMRC to be 30 days. They will specify a date 40 days from the date of issue to allow for delivery, weekend and holidays.
Longer period than 30 days can be specified in the notice, particularly if there is a large amount of information to be provided. The taxpayer should contact the officer immediately it becomes clear that more time is needed. If the officer considers that the request for more time is reasonable they will agree it.
Before turning down a request for more time, the officer will take account of the fact that not being given a reasonable time to comply with a notice is grounds for appeal against it.