VPDS195500 | Vaping Products Duty and Vaping Duty Stamps: Penalties, offences and sanctions: Other fixed and geared regulatory penalties: Forfeiture
From HM Revenue & Customs · Vaping Products Duty and Vaping Duty Stamps guidance
Where a person is liable to a penalty under this part (failure to comply), the following things are liable to forfeiture:
any vaping product or duty stamp to which the failure relates
where the failure relates to a premises, any vaping product or duty stamp found on those premises
This means that any vaping products are liable to forfeiture, irrespective of their duty or stamping status.