art 19 Power to determine without a hearing
(1) Without prejudice to rule 12 above, where either– (a) the parties so agree in writing, or (b) it appears to the Tribunal that the issues raised on the appeal have been determined on a previous appeal brought by the appellant on the basis of facts which did not materially differ from those to which the appeal relates and the Tribunal has given the parties an opportunity of making representations to the effect that the appeal ought not to be determined without a hearing, the Tribunal may determine an appeal, or any particular issue, without a hearing. (2) Before determining any matter under this rule the Tribunal may, subject to rule 17 above, if it thinks fit direct any party to provide in writing further information about any matter relevant to the appeal within such time as the Tribunal may allow.