"31. While we do not draw any adverse inference from S's failure to give evidence or otherwise participate in the hearing of his appeal, we do not feel able to place any weight upon the general denials of guilt, and the bald assertions of innocence, contained in the representations submitted on his behalf. We have to determine his appeal on the evidence and we are left with the position that there has been no challenge by way of evidence, cross-examination or submission, to the open material produced by the respondent."