EAIG17400 | Notifying assessments - forms, letters and schedules: Form EX603 - Excise assessment or civil penalty explanatory notes

You should send a copy of Form EX 603 with every EX 601. It provides information about the codes used on the EX 601 and advises the recipient about the right of appeal against an assessment or civil penalty.

You do not need to send a copy of the fact sheet HMRC 1 (HM Revenue and Customs decisions - what to do if you disagree) with the EX 601 unless the assessed person asks for one.