A sort of related question. I already have the PP (the most comprehensive version, that comes with the Amex Plat charge card.) Now do I need a (departing) BP to access an airside lounge on arrival? (Obviously only relevant in airports that mix arriving and departing pax!)

For eg. if I arrive into BCN on BA, and I do not leave the airside area but in order to kill some time decide to access a PP lounge without an onward connecting BP. Possible? All I'd have would be the stub from the arriving BP, and of course the PP card.