"20. The approach of the High Court in an appeal such as this from a decision of a first-tier tribunal is very clear: absent a patent error of law or findings of fact which simply cannot be justified on the evidence, the High Court will not interfere. A court sitting on appeals such as this will not substitute its own judgment on the facts found by a tribunal merely because it comes to a different conclusion on the facts or the balance to be struck amongst a number of competing factors."