VATAFRS0255 | Operation of the scheme: Penalty for unauthorised issue of flat rate invoices
From HM Revenue & Customs · VAT Agricultural Flat Rate Scheme
The VAT Act 1994 Section 67(1)(c) and Section 67(7) provide for a penalty for the unauthorised issue of flat rate invoices in the following circumstances:
an invoice is issued which does not contain all the details required by the regulations; or
an invoice is issued by a person who was not authorised to do so (i.e. a person who does not have a valid flat rate farming certificate).
If you consider that a penalty may be appropriate, follow the guidance in the VAT civilpenalties manual.