In correspondence with the Minister of State for Transport, the BPA Ltd referred to POPLA as an "Independent Appeals Service".
It has described itself as a "Non-statutory Tribunal"
Now it seems, it is not a tribunal after all, but offers "alternative dispute resolution by way of arbitration". However, it is only available to the motorist for the first 28 days after a rejected appeal to the Private Parking Company and not at any point during a dispute like other arbitration services. Moreover, unlike other arbitration cases it can only find wholly for the Private Parking Company or the motorist and cannot offer any compromise between the parties.
Presumably, the reason any decision is not binding on the motorist as it lacks statutory authority. This is because it is a private arrangement between London Councils and the BPA Ltd and it is doubtful under what authority London Councils are operating it. Since it is a private arrangements, that is why POPLA claims it is exempt from FoI.
But the BPA Ltd would still like to claim that its private operation, paid for by the "industry", and overseen at London Councils by a BPA Ltd Council member has some authority although it is accountable to nobody.
I hope that is clear!