SolvedCH183335 | Dishonest tax agents: file access notice: penalties for failing to comply: time limits
From HM Revenue & Customs · Compliance Handbook
A file access notice must state the date by which the documents must be provided. A person fails to comply with the file access notice if they do not provide all the required documents by the required date. Penalties can be charged if a person fails to comply with a file access notice.
However, we will not charge initial or daily penalties if we allow the person more time to comply with the file access notice, and they comply with the file access notice within that additional time.
See CH883100+ for operational guidance where a person fails to comply with a file access notice.