How to do a compliance check: information powers: taxpayer notice: requests for additional time
You should consider carefully any reasonable request for more time to comply with the information notice. If the person has good reason for needing more time you can agree a revised time scale for production of the information.
Send a letter to the person (copied to the agent where one is acting) saying that you have agreed to allow further time for compliance with the notice dated dd/mm/yy. The information should now be provided by dd/mm/yy. You need not take any further action if this deadline is met.
If you do not consider an extension of the time limit to be appropriate, or you are not satisfied with the person’s explanations you should advise the person (or agent) giving your reasons for refusing the request for more time. You should set out your reasons in writing.
You should be aware that there may still be a right of appeal against the notice, in which case the person (or agent) may appeal on the grounds that you have not allowed sufficient time.