The Upper tribunal judge was being overly harsh… but you do get quite a few of these nutter judges in the immigration courts these days and no justice what so ever…
Anyway, next thing you can do is to seek permission from the Upper Tribunal to appeal to the Court of Appeal (Not High Court!). They will probably refuse it though…
Then you can appeal to the Court of Appeal for permission.
Personally, I think you stand a fairly good chance.
However, because it is going to be in the Court of Appeal, going to a barrister or at least solicitor advocate directly would be a better deal, as OISC and normal solicitor can not appear in the Court of Appeal and they would have to instruct barrister separately.