Interconnected undertaking valuation: related party sales follow prescribed related party valuation; otherwise treated as unrelated for excise valuation. When excisable goods are sold to or through an interconnected undertaking, valuation follows two routes: if the undertakings are related in the statutory sense or the buyer is a holding company or subsidiary company, valuation is determined under rule 9; otherwise the goods are valued as if sold to an unrelated person for the purposes of the valuation provision in section 4(1).