There is no reason why they cannot act as rep, but either the claimant or his/her appointee/deputy would have to sign something that passes muster as an appeal to begin with.
There was a case involving Havering Council where the appeal was signed by a solicitor and this was taken as being done effectively in the name of the claimant: solicitors are presumed to be acting on their client’s instructions. But in this case there is no indication that the claimant/appointee/deputy has instructed or approved the appeal, so I think it fails to satisfy Rule 23 without the signature of the person with a right of appeal.
