Regulation 11 Conclusive effect of a determination on appeal
Where the market value of an asset on a particular date or the apportionment of any amount or value (being a market value or apportionment affecting or which may affect the liability to capital gains tax of two or more persons) is finally determined on an appeal that determination shall, subject to Regulation 14, be in all proceedings relating to capital gains tax conclusive between the Board or any officer of the Board and the following persons—
parties to the appeal; and
any person who was entitled to apply to be joined as a third party in the appeal, and had notice, in reasonable time for making such application, of the appeal and of the question in the appeal entitling him so to apply, not being a person who did so apply without undue delay and whose application was not allowed.
For the purposes of these Regulations—
the determination of an appeal or a question in an appeal shall be treated as final when the determination can no longer be varied by the tribunal making it or by the order of any court;
the market value of an asset on a particular date or the apportionment of any amount or value shall be deemed to have been finally determined on an appeal notwithstanding that there was no dispute concerning that market value or apportionment if the market value or apportionment was a material question in the appeal and the appeal has been finally determined.
The Commissioners shall, if required by any party to an appeal, record in their decision the market value of an asset on a particular date or the apportionment of an amount or value if that market value or apportionment was a material question in the appeal.
The final determination on an appeal of the market value of an asset on a particular date or of the apportionment of any amount or value may be proved in any proceedings relating to capital gains tax by a certificate stating the material particulars signed by the inspector or by the clerk or registrar of the Commissioners or other tribunal who determined the appeal or determined the question in accordance with section 44(6), (7) or (8) of the Finance Act 1965 or in accordance with Regulation 10(3); and a document purporting to be such a certificate may be received in evidence in any such proceedings without further proof.