All appeals are heard in he Court of Appeal which, in practice, means the Royal Courts of Justice in the Strand, London. Like all court hearings , they are open to the public unless there are exceptional circumstances. (Such circumstances might apply for an appeal against a conviction for terrorism, where issues of national security were involved, but they won't apply in the case you refer to).
However, the actual court hearings in the Royal Courts of Justice are usually very brief. The judges have normally studied the papers beforehand and, after a formal submission by the appellant's counsel, they announce their decision. In most cases they uphold the conviction. If not, they'd normally order a re-trial, rather than acquitting the appellant.
Appeals can take a long time to come to court, so you might need to keep checking to see if the case is listed. The switchboard number is 0207 947 6000. The General Enquiries number for the Court of Appeal (Criminal Division) is 020 7947 6011. The Clerk of the Lists (High Court Appeals) can be contacted directly on 020 7947 7354 or 020 7947 7383. (I suspect that the 'General Enquiries number is probably the one you require but I've listed the others just in case they turn out to be of more use).
Chris