CH223800 - How to do a compliance check: information powers: taxpayer notice: non-compliance with a taxpayer notice
If the person does not provide the information or produce the documents you have asked for, you should consider assessing a penalty, see CH270000, unless there is a reasonable excuse for the failure, see CH26300.
If the person has complied with only part of the notice you should attempt to find out why the information or documents have not been provided or produced. The person may be having difficulty locating the information or documents and requires more time.
If the person tells you that they cannot obtain the information, or that a document does not exist and you are satisfied that the claim is genuine, you should set aside the relevant part of the notice.
If documents a person says they cannot supply are available from a third party, for example, bank statements, then you should consider the guidance at CH225160 about mandates to approach banks and at CH225000 about third party notices.
You should not impose a penalty for failure to comply during the appeal period (if any) or while there is an open appeal against the notice. If an appeal is open against only part of the notice, then you may penalise failure to comply with the remainder of the notice.