CH206170 - How to do a compliance check: starting a compliance check: keeping the customer informed
If your case is on hold due to other ongoing actions for example if there is a legal challenge in a lead case, you must inform the taxpayer and BF the case for no more than ten months after the most recent contact.
At the expiration of the BF date, you must update the customer of the current situation.
If, due to the legal challenge, you are still unable to action the case, BF for every additional six months to review the case and contact the taxpayer until you are able to continue working the case in line with the outcome of the legal challenge.