CH227050 | How to do a compliance check: information powers: third party, identity unknown and identification notices issued to banks about their customers: introduction
From HM Revenue & Customs · Compliance Handbook
There may be occasions where your compliance check requires information relating to bank transactions or statement information. You should generally seek this information from the taxpayer themselves, but if the taxpayer does not have the information, or does not provide it, it may be appropriate to seek the information direct from the bank concerned.
Depending on the situation, including the level of taxpayer cooperation with your compliance check, there are two ways you can do this:
You should always consider the least resource intensive option for all parties concerned if this will give you the information you need to complete your check. Therefore, you should always consider the pros and cons of using the mandate option before deciding to apply for a Tribunal-approved Notice.